Multilane Exit Ramps and Diverging Roadways

Posted by on 13/ 11/ 15

Figure 2.47 shows recommended designs for multilane exit ramps and diverging roadways. A diverging roadway is defined as a single roadway that branches or forks into two separate roadways without the use of a speed change lane.

Class I and II diverging roadways should be used when either or both the diverging roadways are mainline roadways of an expressway or a freeway. Class III diverging road­ways should be used at the divergence of directional ramps within an interchange or at the divergence of ramps with non-limited-access roads or streets. In general, class III is applicable at all locations other than those requiring class I or class II.

Lane Balance and Continuity. To have lane continuity, the number of mainline lanes leaving the diverging nose must be equal to the number of mainline lanes approaching the nose. The total number of lanes leaving the diverging nose (mainline lanes plus diverging lanes) must be 1 greater than the total number of lanes approaching the nose to obtain lane balance. The purpose of obtaining lane continuity and lane balance is to avoid a drop lane situation.

It may be necessary to obtain lane balance by adding additional lanes upstream from the diverging nose. The length of each additional lane should be 2500 ft (762 m) and should be introduced using a 0- to 12-ft (3.7-m) taper of 100 ft (30 m) as recom­mended in Fig. 2.47 for the approach roadway class and design speed. There may be conditions off the mainline, such as on collector-distributor roads or within inter­changes, where lane balance and continuity are less important. In such cases, the spe­cial diverging roadway design shown in Fig. 2.47 b may be used.

Terminal Design. The design of diverging roadway terminals is determined by the class and design speed of the approach roadway, and is based on the required neutral gore length L and the required nose width N. Figure 2.47 includes recommended length L and nose width N for various design speeds in diverging roadway classes.

Horizontal Curvature. The inset table in Fig. 2.47 lists recommended values for the diverging curvature (curve differential) between the outer pavement edges of diverging roadways. These values apply only when the alignment between the diverging nose and the PC of the diverging curvature is on tangent or simple curvature. When compounded or spiral curvature is used in the diverging area, it will be necessary to design diverging roadway alignments individually to provide proper L and N for the approach roadway class and design speed.

Multilane Exit Ramps and Diverging Roadways

FIGURE 2.47 Designs for multilane exit ramps and converging roadways. Conversions: 1 mi/h = 1.609 km/h, 1 ft = 0.305 m. (From Location and Design Manual, Vol. 1, Roadway Design, Ohio Department of Transportation, with permission)

 
Подпись: 180

Crest Vertical Curves. When a diverging nose is located on a crest vertical curve, the curve should be designed using the design speed of the approach highway and a stopping sight distance value 25 percent higher than shown in Table 2.18.

Superelevation and Joint Location. The superelevation rate should be based on the design speed of the approach roadway. Superelevation in the terminal area should be designed in accordance with the guidelines given for single-lane ramp terminals (Art. 2.5.2). Longitudinal joints should be located so they will coincide with and define the lane lines.

2.7.2 Four-Lane Divided to Two-Lane Transition

Figure 2.48 shows a reversed curve design (types A and B), a tapered design (type C), and a design for a transition on a curve (type D) for achieving a four-lane divided to two-lane transition. The pavement transition should be located in an area where it can easily be seen. Intersections or drives should be avoided in the transition area. Vertical or horizontal curves should provide preferred stopping sight distance. Reverse curve transitions should normally be used for median widths of 20 ft (6 m) or wider. Taper lengths are based on the design speed of the mainline and are calculated from Eq. (2.5).

MULTILANE RAMP AND ROADWAY TERMINALS AND TRANSITIONS

Posted by on 13/ 11/ 15

When two roadways converge or diverge, the less significant roadway should exit or enter on the right. Left-hand exits or entrances are contrary to driver expectancy and should be avoided wherever possible.

2.7.1 Multilane Entrance Ramps and Converging Roadways

Figure 2.46 shows recommended designs to be used for multilane entrance ramps and converging roadways. Converging roadways are defined as separate and nearly parallel roadways or ramps that combine into a single continuous roadway or ramp having a greater number of lanes beyond the nose than the number of lanes on either approach roadway. High-speed and low-speed entrance terminals should be used in lieu of converg­ing roadway drawings when applicable. High-speed converging roadways should be used when either or both of the converging roadways are mainline roadways of an expressway or a freeway. Low-speed terminals should be used at the convergence of directional ramps within an interchange or at the convergence of interchange ramps with non-limited-access roads or streets. In general, low-speed terminals are applicable at all locations other than those requiring the use of high-speed terminals.

Lane Balance and Continuity. To avoid inside merges, the number of mainline lanes plus converging lanes approaching the nose must be equal to the resultant number of lanes leaving the nose. To make this possible, it is often necessary to carry additional mainline lanes past the nose for an adequate distance prior to tapering back to the desired number of lanes. These details are shown in Fig. 2.46.

Preferential Flow. In Fig. 2.46, one roadway in each design is labeled “preferential flow.” This indicates the more important of the two approaching traffic flows. In selecting the preferential flow, a designer must consider the effect of traffic volumes, number of lanes, the continuity and importance of signed routes, vehicle speeds, and roadway alignment. Lanes carrying the preferential flow are given the higher design treatment. When it is necessary to reduce a number of converging lanes or where an angular change in direction must occur, the design should favor the preferential flow.

Horizontal Curvature. Horizontal curves of roadways approaching the terminal nose should conform to mainline roadway criteria in the case of mainline roadways and to ramp entrance terminal criteria in the case of ramps.

MULTILANE RAMP AND ROADWAY TERMINALS AND TRANSITIONS

Expontlor – {S —————–

Contraction ©

 
Подпись: 176

MULTILANE RAMP AND ROADWAY TERMINALS AND TRANSITIONS

2

Подпись: 177 MULTILANE RAMP AND ROADWAY TERMINALS AND TRANSITIONS

LANE EXIT FROM 4 LANES

TABLE A

 

MULTILANE RAMP AND ROADWAY TERMINALS AND TRANSITIONS

SINGLE LANE CONVERGING WITH MUL T/-LANE

 

MULTILANE RAMP AND ROADWAY TERMINALS AND TRANSITIONS

MUL TI-LANE CONVERGING WITH MUL TI-LANE

 

MULTILANE RAMP AND ROADWAY TERMINALS AND TRANSITIONS

Подпись: 178* Not9* the number of tones leaving the converging nose must be equal to the total nuntber of tones (converging plus main I line I approaching the nose.

MULTILANE RAMP AND ROADWAY TERMINALS AND TRANSITIONS

Distance. Avoidance Maneuver C or E. os per Figure 201-6.

 

Crest Vertical Curves. Crest vertical curves on constant-width roadways approaching the merging nose should be designed to provide sight distance consistent with the design speed of the roadway. Crest vertical curves from the merging nose forward to a point where pavement convergence ceases, and to the converging portion of an approaching roadway where the number of lanes is being reduced in advance of the nose, should be designed using stopping sight distance values 25 percent higher than shown in Table 2.18. When design speeds differ on approaching roadways, the higher of the two design speeds should be used in designing the crest vertical curve beyond the merging nose.

Superelevation and Joint Location. Superelevation in the terminal area should be designed in accordance with the guidelines given for single-lane ramp terminals. Longitudinal joints should be located so they will coincide with and define the lane lines.

Skewness coefficient and kurtosis

Posted by on 13/ 11/ 15

The asymmetry of the PDF of a random variable is measured by the skewness coefficient Yx, defined as

Skewness coefficient and kurtosis

E [(X – ,x)3]

 

_ _M3_ Yx = ,,1.5 ^2

 

(2.40)

 

a

 

Skewness coefficient and kurtosis
The skewness coefficient is dimensionless and is related to the third-order central moment. The sign of the skewness coefficient indicates the degree of symmetry of the probability distribution function. If yx = 0, the distribution is symmetric about its mean. When yx > 0, the distribution has a long tail to the right, whereas yx < 0 indicates that the distribution has a long tail to the left. Shapes of distribution functions with different values of skewness coeffi­cients and the relative positions of the mean, median, and mode are shown in Fig. 2.13.

Similarly, the degree of asymmetry can be measured by the L-skewness coefficient t3, defined as

тз = A.3/A.2 (2.41)

The value of the L-skewness coefficient for all feasible distribution functions must lie within the interval of [-1, 1] (Hosking, 1986).

Another indicator of the asymmetry is the Pearson skewness coefficient, defined as

Подпись:l^x xmo

Y1 =————-

®x

As can be seen, the Pearson skewness coefficient does not require computing the third-order moment. In practice, product-moments higher than the third order are used less because they are unreliable and inaccurate when estimated from a small number of samples. Equations used to compute the sample product – moments are listed in the last column of Table 2.1.

Skewness coefficient and kurtosis Подпись: E [(X - ілх)4] Подпись: (2.43)

Kurtosis kx is a measure of the peakedness of a distribution. It is related to the fourth-order central moment of a random variable as

with kx > 0. For a random variable having a normal distribution (Sec. 2.6.1), its kurtosis is equal to 3. Sometimes the coefficient of excess, defined as ex = kx — 3, is used. For all feasible distribution functions, the skewness coefficient and kurtosis must satisfy the following inequality relationship (Stuart and Ord,

1987)

Подпись: (2.44)Подпись: (2.45)yX + 1 < Kx

By the definition of L-moments, the L-kurtosis is defined as

T4 = Л4/Л2

Skewness coefficient and kurtosis Подпись: (2.46)

Similarly, the relationship between the L-skewness and L-kurtosis for all fea­sible probability distribution functions must satisfy (Hosking, 1986)

Royston (1992) conducted an analysis comparing the performance of sample skewness and kurtosis defined by the product-moments and L-moments. Results indicated that the L-skewness and L-kurtosis have clear advantages

over the conventional product-moments in terms of being easy to interpret, fairly robust to outliers, and less unbiased in small samples.

About the drawings

Posted by on 13/ 11/ 15

The sizes of building elements indicated in the draw­ings in this section are for the purposes of illustrating principles and reminding the designer and the builder to consider their use carefully. These drawings should therefore be used only for reference.

Подпись: w

Подпись: ■ * t
About the drawings

Footings are the part of a foundation that transfers the building’s loads—its weight in materials, contents, occupants, and snow, and possibly wind and earthquake loads—directly to the ground. Consequently, the size and type of footing should be matched carefully to the ground upon which it bears.

Soil type—Concrete footings should be placed on firm, undisturbed soil that is free from organic mate­rial. Soil types are tested and rated as to their ability to support loads (bearing capacity).

Compaction of soil may be required before footings are placed. Consult a soil engineer if the stability of the soil at a building site is unknown.

r SOIL TYPE

BEARING CAPACITY (PSF) 1

Soft clay or silt

do not build

Medium clay or silt

1,500-2,200

Stiff clay or silt

2,200-2,500

Loose sand

1,800-2,000

Dense sand

2,000-3,000

Gravel

2,500-3,000

Bedrock

4,000 and up

Reinforcing—Most codes require steel reinforcing rods (called rebar) in footings. Rebar is a sound invest­ment even if it is not required, because it gives tensile strength to the footing, thereby minimizing cracking and differential settling. Rebar is also the most common way to connect the footing to the foundation wall. For rebar rules of thumb, see 5B.

Size—Footing size depends mainly on soil type and the building’s weight. The chart below shows footing sizes for soils with bearing capacities of 2,000 pounds

per square foot

(psf).

Г NO. OF STORIES

H

W

1

6 in.

12 in.

2

7 in.

15 in.

3

8 in.

18 in.

A rule of thumb for estimating the size of standard footings is that a footing should be 8 in. wider than the foundation wall and twice as wide as high.

Frost line—The base of the footing must be below the frost line to prevent the building from heaving as the ground swells during freezing. Frost lines range from 0 ft. to 6 ft. in the continental United States. Check local building departments for frost-line requirements.

@ FOOTINGS

LENGTH OF
REBAR STUB
EQUALS
30 BAR
DiAMETERS

(MiN.)

 

LOCATE vERTIcAL Rebar

per local code & AT
center of cells for
block foundation.

concrete or
concrete-block
foundation wall
backfill

 

LENGTH of
REBAR STuB

equals
30 BAR
diameters

(MIN.)

 

locate vertical rebar
per local code & AT
center of cells for
block foundation.

concrete or
concrete-block
foundation wall
backfill

BEND bottom of
REBAR & ALTERNATE

direction of bend.

 

drainpipe SEE 18A

 

horizontal rebar per local code

 

horizontal rebar
per local code

note

for h & w SEE 3

 

BEND bottom of
REBAR & ALTERNATE

direction of bend.
note

for h & w SEE 3

 

locate bottom of footing on level, undisturbed soil below frost line.

 

locate bottom of footing on level, undisturbed soil below frost line.

 

A TRENCH FOOTING

 

TYPICAL FORMED FOOTING

 

REBAR continuous THRouGH STEp

 

MULTIPLES OF 8 IN. FOR CONCRETE-BLOCK FOUNDATION WALL (MAX. DEPTH 2A IN.)

 

11/2-IN. By 3-in.
(Approx.) KEyWAy
locks footing
to cast-in-
place concrete
foundation wall.

 

concrete foundation wall

 

backfill

 

horizontal rebar
per local code
drainpipe
SEE 18A

 

note

keep cut in soil
AS vertical
AS possible
AT step in
footing.

 

locate bottom
of footing
on level,
undisturbed
soil below
frost line.

 

note

use KEyWAy footings oNLy
with concrete foundation

WALLS WHERE LATERAL LoADS on

foundation are not significant.
use footings doweled with
vertical rebar for lateral loads.

 

min. width equals depth of footing.

 

locate bottom of footing on level, undisturbed soil below frost line.

 

FOOTING WITH KEYWAY

 

STEPPED FOOTING

 

About the drawingsAbout the drawingsAbout the drawingsAbout the drawings

About the drawings

Code requirements for rebar use may vary, but a few rules of thumb can be helpful guidelines. Verify with local codes first.

Sizes—Rebar is sized by diameter in Vs-in. incre­ments: #3 rebar is 3/8-in. dia., #4 is Уг-in. dia., #5 is 5/8-in. dia., etc. The most common sizes for wood-frame construction foundations are #3, #4, and #5.

Overlapping—Rebar is manufactured in 20-ft. lengths. When rebar must be spliced to make it contin­uous or joined at corners, the length of the lap should equal 30 bar diameters, as shown below.

30 BAR DIAMETERS

t——- —f

 

EDGE OF MASONRY FiREBOX

 

tie firebox TO

FOOTING AT

corners with

REBAR Dowels.

verify with local codes.

 

6-iN. (MiN.) PROJECTiON BEYOND FIREBOx

or chimney masonry

 

12-iN. (MiN.) DEpTH

without rebar

 

tie fireplace & foundation FOOTING with REBAR.

 

Clearance—The minimum clearance between rebar and the surface of the concrete is 3 in. for footings, 2 in. for formed concrete exposed to backfill or weather, and 3/4 in. for formed concrete protected from the weather.

 

locate BOTTOM of footing below FROST line.

 

FIREPLACE FOOTING

 

REBAR RULES OF THUMB

 

About the drawingsAbout the drawings

Column footings (also called pier pads) support col­umns in crawl spaces and under porches and decks. Place all footings on unfrozen, undisturbed soil free of organic material. The bottom of the footing must be located below the frost line unless it is within a crawl space. Columns may need to be anchored to column footings to prevent uplift caused by wind or earthquake forces (see 6B).

Typical sizes are 12 in. to 14 in. for square footings or 16-in. to 18-in. diameter for round footings.

Extreme loads may require oversize footings. The vertical load divided by the soil bearing capacity equals the area of footing, e. g.,

6,000 lb. – 2,000 psf = 3 sq. ft.

To prevent moisture in the footing from damaging the column, use a pressure-treated wood column or place a 30-lb. felt moisture barrier between an untreated wood column and a concrete footing, or use steel connectors where required (see 6B).

A COLUMN FOOTINGS

About the drawings

I 44

L

 

About the drawings

Подпись: Wet Base THIS GALVANIZED STEEL BASE MUST BE PRECISELY LOCATED IN WET CONCRETE. AVAILABLE WITH STANDOFF TO RAISE THE WOOD COLUMN ABOVE THE CONCRETE.

Single Strap

GALVANIZED STEEL STRAP IS OFTEN USED IN CRAWL SPACES OR UNDER PORCHES.

NOTE

USE PT. WOOD COLUMN OR PLACE 30-LB. FELT MOISTURE BARRIER BETWEEN UNTREATED POST & CONCRETE.

Adjustable Base

MULTIPLE-PIECE GALVANIZED STEEL ASSEMBLY ALLOWS FOR SOME LATERAL ADJUSTMENT BEFORE NUT IS TIGHTENED. BASE ELEVATES WOOD COLUMN ABOVE CONCRETE FOOTING.

Drilled Base

EXPANSION BOLTS ARE DRILLED INTO FOOTING OR SLAB AFTER CONCRETE IS FINISHED. ALLOWING FOR PRECISE LOCATION OF COLUMN.

NOTE

EXPANSION BOLTS REQUIRE SPECIAL INSPECTION IN MOST JURISDICTIONS

COLUMN BASE CONNECTORS

About the drawings

Подпись: FOUNDATION WALLS Concrete & Concrete Block
About the drawings

Foundation walls act integrally with the footings to support the building. They also raise the building above the ground. The primary decision to make about foun­dation walls is what material to make them of. There are several choices:

Concrete block—Also known as concrete masonry unit or CMU construction, concrete block is the most common system for foundation walls. Its primary advantage is that it needs no formwork, making it appropriate in any situation, but especially where the foundation is complex. Concrete masonry will be used most efficiently if the foundation is planned in 8-in. increments, based on the dimensions of standard con­crete blocks (8 in. by 8 in. by 16 in.).

Cast concrete—Concrete can be formed into almost any shape, but formwork is expensive. The most eco­nomical use of cast concrete, therefore, is where the formwork is simple or where the formwork can be used several times. Cast-in-place concrete is used for forming pier and grade-beam systems, which are especially appropriate for steep sites or expansive soils (see 13).

Reinforcing—Some local codes do not require rein­forcing of foundation walls. Codes in severe earthquake zones are at the other extreme. As a prudent minimum,
all foundation walls should be tied to the footing with vertical rebar placed at the corners, adjacent to all major openings, and at regular intervals along the wall. There should be at least one continuous horizontal bar at the top of the wall. Joint reinforcing may be an ade­quate substitute (see 10B).

Width—The width of the foundation wall depends on the number of stories it supports and on the depth of the backfill, which exerts a lateral force on the wall. With minimum backfill (2 ft. or less), the width of the wall can be determined from the chart below.

The design of basement walls and foundation walls retaining more than 2 ft. of backfill should be verified by an engineer or an architect.

The minimum height of a foundation wall should allow for the adequate clearance of beams and joists from the crawl-space floor. A code-required 18-in. clearance usually requires 12-in. to 24-in. foundation walls, depending on the type of floor system.

r NO. OF STORIES

FOUNDATION WIDTH

1

6 in.

2

8 in.

2

10 in.

Подпись: AN 8-iN. OR 10-IN.- DEEP SCREENED VENT MADE TO BE CAST IN PLACE IN CONCRETE BLOCK OR CONCRETE FOUNDATION WALL Подпись: AN 8-IN. X 16IN. SCREENED VENT THAT FITS IN PLACE OF ONE CONCRETE BLOCK Подпись: ONE OF vARIOuS pLASTIC OR METAL VENTS MADE TO VENT THROUGH THE RIM JOIST AND FASTEN TO wOOD SIDING. CARE MuST BE TAKEN TO INSTALL PROPER FLASHING Moisture— Even with the best drainage, the soil under crawl spaces always carries some ground mois­ture, which will tend to migrate up to the crawl space in the form of vapor. This vapor can be substantially controlled with a vapor retarder laid directly on the ground, which must first be cleared of all organic debris. Crawl-space vapor retarders should be 6-mil (min.) black polyethylene. The dark plastic retards plant growth by preventing daylight from reaching the soil. Adding a concrete rat slab over the vapor retarder will enhance its effectiveness and durability.

Moisture cannot be allowed to build up in a crawl space where it can create catastrophic damage caused by mildew, fungus, and other organisms dependent on moisture. There are two basic strategies to remove the moisture – ventilation to the outside, and conditioning the air as part of the air volume inside the building.

In both cases, air is moved through the crawl space to replace moisture-laden crawl-space air.

Ventilation—Crawl-space cross ventilation minimizes the buildup of excess moisture under a structure. In some regions, crawl-space ventilation is also required to remove radon gas.

The net area of venting is related to the under-floor area and to the climatic and groundwater conditions. Most codes require that net vent area equals У150 of the under-floor area with a reduction to У1500 if a vapor barrier covers the ground in the crawl space. Screened vents should be rated for net venting area.

Vents should supply cross ventilation to all areas of the crawl space. Locating vents near corners and on opposite sides of the crawl space is most effective.

Access doors can provide a large area of ventilation. Wells allow vents to be placed below finished grade.

As shown in the drawing above right, screened vents are available for installing in masonry, cast concrete, and wood. They are available in metal or plastic, and some have operable doors for closing off the crawl space during winter to conserve heat. Operable vents should be closed only during extreme weather con­ditions. Closing the vents for an entire season will increase moisture in the crawl space and can signifi­cantly increase the concentration of radon gas.

A CRAWL-SPACE CONTROLS_______

Unvented crawl space – In climates with humid summer weather, ventilation actually brings moisture into a crawl space, where hot, humid air contacts cooler surfaces in the crawl space and condenses there. The best solution in this case is to insulate the crawl space, close it up tight, and heat and cool it as if it were another room. It doesn’t add much to the heating or cooling load, being a small volume with little exterior wall area. This strategy is also appropriate in other climates.

Unvented crawl spaces must be insulated at the foundation wall. The insulation can be installed using the same details as for a basement wall (see 15C). Care must be taken to seal the space well against air infiltra­tion. This includes sealing the joint between foundation wall and mudsill (see 12A) and sealing the joints of the floor assembly that bears on the mudsill (see 33-34).

Pests—Rodents and other large burrowing pests can be kept out of crawl spaces by means of a “rat slab,” which is a 1-in. to 2-in.-thick layer of concrete poured over the ground in a crawl space. A concrete-rated moisture barrier should be placed below this slab (see 20). Termites and other insect pests are most effectively controlled by chemical treatment of the soil before con­struction begins.

Radon—Radon is an odorless radioactive gas that emerges from the ground and is present at very low concentrations in the air we breathe. This gas can build up to dangerous levels when trapped in a crawl space (or basement). Although present everywhere, radon concentration levels in the earth are higher in some regions, and all of North America has been mapped and evaluated for radon danger. The best protection against radon buildup is to ventilate the crawl space well and/or effectively seal the ground below the building. Radon test kits are readily available.

About the drawingsПодпись: Bond or Lintel CUT HALF, CORNER, AND OTHER BLOCKS ON SiTE TO CONTiNUE BOND BEAMS TO THE END OF WALLS AND AROUND CORNERS. Подпись: CornerПодпись: iN.About the drawingsAbout the drawings

Stretcher or Regular

STANDARD WiDTHS ARE 35/8 iN.,

55/8 iN., 75/8 iN., 95/8 iN., AND 115/8 iN. ALL DiMENSiONS ARE ACTUAL.

Jamb

JAMB BLOCKS ARE AVAiLABLE iN HALF (SHOWN) AND STRETCHER SiZES. iN ONE SiDE A SLOT LOCKS BASEMENT WiNDOWS iN PLACE.

NOTE

ALMOST ANY SiZE OR SHAPE OF MASONRY WALL CAN BE BUiLT WiTH BASiC BLOCK TYPES. CONSULT NCMA FOR CONSTRUCTiON TECHNiQUES AND FOR SPECiAL BLOCKS WiTH SPECiAL EDGE CONDiTiONS, TEXTURES, COLORS, AND SiZES.

(A CONCRETE-BLOCK TYPES

 
About the drawings

FLOOR SYSTEM

P. T. MUDSiLL SEE 12A

BOND BEAM WiTH # 4 REBAR AT TOP COURSE OR BELOW VENT OPENiNG. FOR JOiNT­REiNFORCiNG ALTERNATiVE SEE 10B

BACKFiLL

VERTiCAL REBAR

 

BLOCK FOR VENT OMiTTED AS NEAR AS POSSiBLE TO CORNER SEE 8A

 

FULL MORTAR BASE WHERE LATERAL LOADS APPLY

SLOPE TOP OF FOOTiNG WiTH MORTAR.

DRAiNAGE SEE 18A

 

VERTiCAL REBAR AT CORNER, ADJACENT TO OPENiNGS & iN CELLS CONTAiNiNG ANCHOR BOLTS

 

FOOTiNG

 

CRAWL-SPACE FOUNDATION WALL

Concrete Block

 

CORNER & VENT OPENING

Concrete-Block Foundation Wall

 

About the drawingsAbout the drawings

NOTE

Подпись: NOTE TO REINFORCE A JOINT, A wELDED HEAVY-WIRE TRUSS MAY BE SUBSTITUTED FOR HORizONTAL REBAR IN MANY CASES. IT IS EMBEDDED IN THE MORTAR jOiNTS BETwEEN COURSES OF MASONRY. Подпись: COURSES BELOw About the drawings

Подпись: CONCRETE-BLOCK FOUNDATION Joint-Reinforcing Alternative
Подпись: CONCRETE-BLOCK FOUNDATION Rebar Placement

HORiZONTAL REBAR SHOULD BE CONTiNUOUS iN A BOND BEAM AT THE TOP COURSE, OR AT THE SECOND COURSE iF FOUNDATiON VENTS ARE LOCATED iN THE TOP COURSE. HORiZONTAL REBAR MAY ALSO BE LOCATED iN Intermediate BOND Beams If THE HEiGHT, wiDTH & Function OF THE wALL REQUIRE IT.

About the drawings

BOND-BEAM TOp COURSE wiTH reinforcing SEE 10A

BOND OR LINTEL BLOCKS wiTH GROUT AND REBAR OR REINFORCED CAST- CONCRETE LINTEL vertical REBAR AT BOTH SIDES of opening AND extended INTO FOOTING

CORNER AND HALF

blocks at side jambs

About the drawings

CONCRETE-BLOCK BASEMENT

Opening within Wall

CONCRETE-BLOCK BASEMENT

Opening at Top of Wall

About the drawings
About the drawings

BRICK-VENEER FOUNDATION

Brick below Mudsill
brick-veneer foundation

Brick Level with Mudsill

About the drawingsAbout the drawings

1/2-iN. STEEL ANCHOR BOLT AT 4 FT. OR 6 FT. O. C.

(MAX.) & 12 iN. (MAX.) FROM END OF EACH PiECE OF MUDSiLL. verify wITH LOcAL CODES.

1/2-iN. STEEL NUT WITH STEEL WASHER

2X4 OR 2X6 P. T. WOOD MUDSiLL

SILL GASKET OF CAULK OR FIBERGLASS AT BASEMENTS OR OTHER LIVING SPACE

CONTINUOUS

termite shield in termite regions

CONCRETE OR CONCRETE-BLOCK FOUNDATION WALL REBAR

7-IN. MiN. DEPTH OF ANCHOR BOLT INTO FOUNDATION WALL

NOTE

SOME CODES REQUIRE LONGER BOLTS FOR MASONRY WALLS.

BEND DOUBLE-STRAP ANCHOR AROUND MUDSiLL & NAIL AT SIDE & TOP, OR NAIL ONE STRAP TO MUDSiLL & OTHER TO FACE OF STUD.

2X4 OR 2X6 P. T. WOOD MUDSiLL

SILL GASKET OF CAULK OR FIBERGLASS AT HEATED SPACE

PLACE MUDSiLL ANCHORS INTO FRESH CONCRETE OR NAIL TO FORM BEFORE PLACING CONCRETE.

SLAB WITH TURNED – DOWN FOOTING SEE 22

NOTE

VERIFY ACCEPTABILITY OF MUDSiLL
ANCHOR WITH LOCAL BUILDING CODE.
THE MUDSiLL ANCHOR ALLOWS THE
ABILITY TO FINISH SLAB TO THE EDGE
BUT IT IS DIFFICULT TO USE WITH
TERMITE SHIELD.

MUDSILL WITH ANCHOR BOLT

MUDSILL WITH MUDSILL ANCHOR

A CRIB WALL IS AN ALTERNATIVE TO COLUMNS & A BEAM SUPPORT FOR JOISTS IN A CRAWL SPACE. IT ALLOWS MORE CLEARANCE FOR DUCTS AND EQUIPMENT & AVOIDS THE POTENTIAL PROBLEM OF CROSS-GRAIN SHRINKAGE IN BEAMS.

A PONY WALL IS USEFUL IN A STEPPED FOUNDATION WALL OR IN A SLOPING PIER & GRADE-BEAM FOUNDATION. THE PONY WALL PROVIDES A LEVEL SURFACE FOR CONSTRUCTION OF THE FIRST FLOOR.

Подпись:Подпись: FOUNDATION WALL OR GRADE BEAMAbout the drawingsПодпись: JOISTSПодпись: SINGLE TOP PLATEПодпись: CRIB STUDS PLACED DIRECTLY BELOW EACH JOISTAbout the drawingsПодпись: NOTE CRIB WALL IS BRACED BY PERIMETER FOUNDATION WALL.DOUBLE TOP PLATE CONTINUOUS WITH MUDSiLL

PONY WALL RECEIVES THE SAME EXTERIOR FINISH AS THE FRAMED WALL ABOVE.

Подпись: CRIB WALLPONY WALL

FOUNDATIONS

Pier & Grade-Beam Systems

 

NOTE

piER & grade-beam foundation systems

ARE particularly SuiTED TO ExpANSivE SOILS or steep hillsides. they are also useful TO avoid damaging nearby tree ROOTS. pier & GRADE-BEAM

SYSTEMS MuST BE ENGINEERED.

 

GRADE BEAM CAN SLOPE TO CONFORM TO CONTOUR

 

PONY WALL ON TOP OF GRADE BEAM MAKES A LEVEL SURFACE FOR FLOOR CONSTRUCTiON SEE 12D —

 

GRADE BEAM SEE 13C

 

pier SEE 13B

 

A PIER & GRADE-BEAM SYSTEMS

 

p. T. mudsill SEE 12A

 

GRADE BEAM SEE 13C

continuous pier

REBAR TIED TO GRADE BEAM

Backfill & DRAINAGE SEE 18A

 

continuous rebar

ENGINEERED & TIED TO pier REBAR

BACKFILL

drainpipe if required SEE 18A

FOAM CuSHION ALLOWS ExpANSivE SOIL TO RISE WITHOuT. U – V.. LIFTING FOuNDATION.

p. T. MuDSILL SEE 12A

 

SMOOTH top EDGE OF pier TO allow SOIL TO expand without

LIFTING piER.

 

continuous rebar

ENGINEERED & TIED to pier REBAR

BACKFILL

drainpipe if required SEE 18A

v-SHApE ALLOWS expansive SOIL TO RISE WITHOuT LIFTING

foundation.

 

CAST CONCRETE piER

typical pier

DIAMETERS ARE 12 IN. TO 18 IN. SpACING varies & depths RANGE TO 20 FT., DESCENDING ON SOIL.

ENGINEER SizE & TYpE OF REBAR.

 

PIERS FOR GRADE BEAM

 

 About the drawings

About the drawingsAbout the drawingsAbout the drawingsAbout the drawings

About the drawings

CONCRETE BASEMENT WALL SEE 15B

 

CONNECTiON TO WOOD FLOOR’

JOiSTS ON MUDSiLL SEE 33A & B JOiSTS FLUSH WiTH MUDSiLL SEE 33C & D JOiSTS BELOW MUDSiLL SEE 34

 

CONNECTiON TO STuD wALLS SEE 15D

 

pilaster SEE 16A

 

buttress SEE 17C

 

CONNECTiON TO CONCRETE Slab SEE 21C & D

 

waterproofing SEE 18C

 

NOTE

for basement walls, vERiFy thickness

Of CONCRETE OR CONCRETE BLOCK; SizE, AMOuNT, AND pLACEMENT OF REBAR; STRENGTH OF CONCRETE OR GROuT; AND CONNECTiON TO FLOOR SySTEMS WiTH AN ARCHITECT OR Engineer.

 

DRAINAGE SEE 18B

 

counterfort SEE 17A & B

 
About the drawings

Retaining walls—Retaining walls resist lateral loads from the bottom only. They rely on friction at the base of the footing and soil pressure at the outside face of the footing to resist sliding. The weight of the wall and the weight of soil on the footing resist overturning.

 
About the drawings

Buttresses and counterforts strengthen retaining walls in much the same way that pilasters strengthen basement walls (see 17). Buttresses help support retaining walls from the downhill side, and counterforts from the uphill side.

Technically, freestanding retaining walls are not a part of the building, but they are included here because they are typical extensions of the building components (foundation and basement walls) into the landscape.

 

^ BASEMENT & RETAINING WALLS

 

About the drawings

About the drawingsПодпись:Подпись:Подпись:Подпись:Подпись:Подпись:About the drawingsПодпись: о°л°0ОО§° О 00OLOQ0°Подпись:About the drawings

iNSULATiON SEE 15C

BACKFILL AND DRAiNAGE SEE 18B

WATERPROOFING SEE 18C

ALTERNATIVE LOCATION FOR INSULATION

VERTICAL REBAR PLACED AT TENSION SIDE OF WALL RESISTS BENDING FORCES.

BOND BEAMS

as required BY engineering

vertical rebar

ANCHORS wALL TO FOOTING.

SLAB SEE 21C OR D

full mortar joint on roughened

FOOTING

FOOTING SEE 4
insulation SEE 15C

backfill AND DRAINAGE SEE 18B

waterproofing SEE 18C

alternative location FOR insulation

vertical rebar placed at tension SIDE OF wall RESISTS BENDING FORCES.

horizontal rebar as required by

ENGINEERING

vertical REBAR ANCHORS wALL TO FOOTING.

SLAB

SEE 21C OR D

FOOTING SEE 4

About the drawings

About the drawings

BASEMENT WALL

Concrete Block

BASEMENT WALL

Concrete

Подпись:About the drawingsПодпись: NOTE DO NOT uSE CONTINUOUS VAPOR BARRIER ON wARM SIDE OF wALL BELOW GRADE. SEE 18C Heated basements must be insulated at their perim­eter walls. The amount of insulation required depends on the climate. There are two ways to insulate base­ment walls—from the exterior or from the interior.

About the drawingsExterior—Exterior insulation should be a closed-cell rigid insulation (extruded polysty­rene or polyisocyanurate) that will not absorb moisture. This insulation, available in 2-ft. or 4-ft. by 8-ft. sheets, is attached directly to the basement wall with adhesive or mechanical fasteners. It may be applied either under or over the waterproofing, depending on the type.

Interior—Interior insulation may be either rigid or batt type. Petroleum-based rigid types must be covered for fire protection when used in an interior location. Other rigid insulation, such as rigid mineral fiber, need not be fire – protected. Building a stud wall with batt insu­lation has the advantage of providing a nailing surface for interior finishes.

About the drawings

BASEMENT iNSULATiON

 

1/2-IN. air space at end

OF WOOD BEAM OR USE p. T. WOOD OR STEEL

 

1/10 OF THE DiSTANCE BETWEEN VERTiCAL SUPPORTS (OTHER PiLASTERS, CORNERS, OR WALLS)

 

NOTE

USE LAMINATED WOOD OR STEEL BEAM TO MINIMIZE SHRINKAGE.

 

1/2-in. air space

 

BEAM

 

30-LB. FELT UNDER BEAM AT pOINT OF CONTACT WITH CONCRETE OR CONCRETE BLOCK

SHIMS TO LEVEL BEAM

3-IN. MINIMUM BEARING SURFACE FOR WOOD BEAM

 

NOTE

proportions for pilaster dimensions are approximate. rebar in wall, pilaster & FOOTING must BE engineered.

 

footing SEE 4

 

pilaster

 
About the drawings About the drawings

FRAMED WALL

1/2-in. air space

BLOCKING AS REQUIRED

BEAM WITH 1V2-IN. DECKING SEE 47C & D OR BEAM & JOIST SYSTEM SEE 33C

ATTACH BEAM TO COLUMN

 

1/2-IN. air space at

END AND SIDES OF WOOD BEAM OR USE p. T. WOOD OR STEEL

 

NOTE USE LAMINATED WOOD OR STEEL BEAM TO MINIMIZE SHRINKAGE.

 

NOTCH BEAM FOR MUDSILL IF REQUIRED (MAX. NOTCH EQUALS 1/4 DEpTH OF BEAM).

 

4X4 WOOD OR p. T. WOOD COLUMN

WOOD COLUMN BEARS ON FOOTING. IF ATTACHMENT IS REQUIRED SEE 6B

 

1/2-in. air space

BEAM

30-LB. FELT UNDER BEAM AT pOINT OF CONTACT WITH CONCRETE OR CONCRETE BLOCK

SHIMS TO LEVEL BEAM

3-IN. MINIMUM BEARING SURFACE FOR WOOD BEAM

 

30-LB. FELT UNDER COLUMN AT FOOTING OR USE p. T. WOOD

 

CONCRETE OR CONCRETE-BLOCK FOUNDATION WALL

 

BEAM POCKET

 

WOOD-COLUMN BEAM SUPPORT

Basement or Crawl-Space Wall

 

Concrete or Concrete Block

 

About the drawingsAbout the drawingsAbout the drawingsAbout the drawingsAbout the drawings

About the drawings

NOTE

Подпись:

Подпись: COUNTERFORT REBAR About the drawings

About the drawings

Подпись: 0 CONCRETE COUNTERFORT Подпись: CONCRETE-BLOCK COUNTERFORT

COUNTERFORT MUST BE pROFESSIONALLY ENGiNEERED. REiNFORCEMENT iS REQUiRED FOR TENSiON AND SHEAR.

NOTE

Подпись: WITH WALL FOOTING

BUTTRESS & RETAINING WALL MUST BE PROFESSIONALLY ENGINEERED.

BUTTRESS

Concrete or Concrete Block

According to the European Standard EN 13108-5

Posted by on 13/ 11/ 15

The requirements for gradation of SMA mixtures have been provided in the European standard PN-EN 13108-5 (see Chapter 14). This standard does not set out the crite­ria and conditions for selecting the particular gradation of a mixture. Establishing these criteria remains the responsibility of each CEN-member state. In Figures 14.2 through 14.5, examples of gradation limits are presented.

6.1 GENERAL RULES

6.2.1 Original Zichner’s Proportions

In his publications (Zichner, 1971; Zichner, 1972) Dr. Zichner described a recom­mended composition of an SMA mixture as follows:

• The stone content should be about 65-80% (m/m), preferably 70-75%, using only crushed stones.

• The main rule governing gradations is that the mixture is composed “so that the percentage of the coarser size is greater than that of the smaller size.”

• Mastic content is 20-35% (m/m).

• 23-28% of the mastic is a binder.

• For layers with different thicknesses, different types of stones should be used as follows:

• Thickness less than 3 cm—stone fractions 2/5.6 and 5.6/8 mm in pro­portions of 25 and 75%, respectively

• Thickness 3-4.5 cm—stone fractions 2/5.6, 5.6/8, and 8/12 mm, or only 5.6/8 and 8/12 mm

• Thickness greater than 4.5 cm—stone fractions 2/5.6, 5.6/8, 8/12, and 12/18 mm

• Only manufactured sand should be used in the mastic.

Looking at Zichner’s MASTIMAC and MASTIPHALT gradation curves presented in Chapter 1 (see Figure 1.1), we can find approximate contents of aggregate frac­tions (Table 6.4).

The proportions of different fractions of coarse aggregates used in current German SMA mixtures are presented also in Chapter 2 (see Table 2.1) after the German DAV Handbook (Druschner and Schafer, 2000).

Plumb bob

Posted by on 13/ 11/ 15

As its name implies, a plumb bob is used to check a vertical surface—-such as a door, wall, or window—-for plumb, or to find a spot directly below any given point. It is a simple but very accurate tool consisting of a tapered weight attached to a string. It’s really easy to use, too. To find plumb below a spot on a ceiling joist, for example, hold the string to a point on a joist and extend the string so that the weight is close to the floor (see the photo on the facing page). Plumb is directly below the point of the weight.

Plumb bob

A plumb bob is a very accurate tool for finding the location of a point that is directly above or below another point.

 

The Material Safety Data Sheet (MSDS)

Posted by on 13/ 11/ 15

The Material Safety Data Sheet (MSDS) pro­vides information about the chemical sub­stances in a product, its handling precautions,

and its known health effects. The responsi­bility for preparing the MSDS lies with the chemical manufacturer. All manufacturers are required to create an MSDS for every chemi­cal compound they offer. The following infor­mation must be included:

• with the exception of trade secrets, the spe­cific chemical name and common names for hazardous ingredients

• physical and chemical characteristics

• physical hazards

• health hazards

• primary routes of entry to the body

• OSHA permissible exposure limit (PEL) and any other recommended exposure limit

• whether the chemical is a confirmed or potential carcinogen

• precautions for safe handling and use

• emergency and first aid procedures

• name, address, and telephone number of the manufacturer or other responsible party.

MSDSs can be obtained from either the dis­tributor or the manufacturer of the product in question.

What an MSDS Will Not Tell You

There is important information that an MSDS does not reveal. Thanks to the Trade Secrets Act, companies are not required to list ingre­dients they define as trade secrets. Although the OSHA Hazard Communication Standard requires that an MSDS list all health effects, the health effects of trade secret ingredients can be exempted.2 Furthermore, hazardous ingredients that are present in amounts of less than i percent and carcinogens present in amounts less than o. i percent need not be listed. Another significant omission is the lack of disclosure of “inert” ingredients, which can account for up to 90 percent or more of prod­uct volume. Some of these so-called inert in­gredients are more hazardous than the active ingredients.3

Although the consumer is not allowed ac­cess to the unlisted information, one of the codes under the same law (OSHA Hazard Communication Standard 29, Code of Fed­eral Regulation 1910.1200) permits physicians and other health care providers to access all product ingredient information for diagnostic and treatment purposes. Most doctors are un­aware of their right to know.

The permissible exposure levels (PELs) set by OSHA and the threshold limit values (TLVs) established by the American Confer­ence of Governmental Industrial Hygienists (ACGIH) are misleading. Industry interests have played a major role in establishing these exposure limits, most of which were set with­out prior testing.4 The small amount of testing that has been carried out was based on expos­ing rats to a single dose of a single chemical, with cancer or death as the end point. In real­ity, people are exposed to hundreds of chemi­cals at a time. These chemicals can accumulate in the body tissues over time and their effects can be synergistic. Monitoring for cancer or death does not take into account the many noncarcinogenic effects of chemicals, such as damage to the nervous, endocrine, and im­mune systems. It is important to recognize that workplace standards are not set for the safety of the worker but rather for what is con­sidered feasible for industry.

Health effects listed in an MSDS are often vague and misleading. They are most accurate when listing the acute, short-term effects, such as eye and nose irritation, rashes, and asthma. The data on chronic, long-term exposure are often lacking and do not take into account cu­mulative or synergistic effects.

Traffic Loading and Location

Posted by on 13/ 11/ 15

Coarse-graded mixtures make stronger skeletons. That is why the majority of requirements for SMA contain a noticeable tendency toward increasing the maxi­mum particle size in a mixture in conjunction with an increase in the traffic loading. When selecting a mixture, both the strengths and weaknesses of an accepted solution
should be considered; mixtures with larger maximum particle size (let us suppose greater than 10 mm) are characterized by higher rut resistance but lower noise reduc­tion ability and poorer skid resistance. Therefore, when at all possible, SMA 0/11 is being gradually abandoned for SMA 0/8.

In Germany, SMA 0/8S and 0/11S have been used on the most heavily trafficked roads while on lesser trafficked roads mixtures without an S marking are used. The guidelines from 2001 to 2007 (ZTV Asphalt-StB 01 and ZTV Asphalt-StB 07, respec­tively) have differentiated mixtures according to traffic, with the understanding that mixtures with the same maximum aggregate size but intended for various traffic loadings differ in the shape of the gradation limits. German SMA aggregate mixes of the S type differ from the lower traffic SMAs in that they have the following:

• Lower filler contents

• Lowered gradation limit curves

• No non manufactured (natural) sand

As a result, German SMA mixtures of the “S” type should be coarser and, at the same time, less closed. This is logical since there should be more voids in a heavily trafficked course (refer also to the Dutch method in Chapter 7).

Подпись: TABLE 6.3 SMA Division according to the Traffic Category Prevailing in Locations SMA mixes with Gradation canada germany united (ontario) ZTV States OPSS. Asphalt- NAPA MUNI application stb 07 IS 128 1151 Low and medium traffic roads 0/8N, 0/5N Principal 0/11S, 0/9.5, 0/9.5, roads and 0/8S 0/12.5, 0/12.5, highways (heavy traffic) 0/19 0/19
In many countries, as in Germany, different SMA gradation curves have been specified depending on the traffic category (traffic loading), as shown in Table 6.3.

slovakia

Poland

slovenia

sist

Australia

klaz

WT-2

1038-

NAs 2EcI

1/2008

2008

5:2008

2004

—

0/5,

0/4, 0/8,

0/7, 0/10

0/8

0/11

0/8,

0/8,

0/8, 0/11 0/10, 0/14

0/11,

0/11

0/16

COLLECTOR-DISTRIBUTOR ROADS

Posted by on 13/ 11/ 15

Collector-distributor (C-D) roads are used to minimize weaving problems and reduce the number of conflict points (merging and diverging) on the mainline. C-D roads may be used within a single interchange, through two adjacent interchanges, or continuously through several interchanges.

2.6.1 Design of C-D Roads

When a C-D road is provided between interchanges, a minimum of two lanes should be used. Either one or two lanes may be used on C-D roads within a single interchange. The cross-section elements for one – and two-lane C-D roads should be in accordance with the criteria for one-lane and two-lane directional roadways provided in Fig. 2.27. The separation between the mainline and C-D road pavements should be designed to prevent, or at least discourage, indiscriminate crossovers. As a minimum, the separa­tion should be wide enough to provide normal shoulder widths for both the mainline and C-D road roadways plus a suitable median. Normally, a standard concrete barrier median is used, since C-D road separation often involves obstructions such as bridge parapets, piers, or overhead sign supports. There may be isolated cases where a lesser – type median may be used.

Подпись: 174COLLECTOR-DISTRIBUTOR ROADS

2.6.2 C-D Road Entrance and Exit Terminals

Figure 2.45a shows both high-speed and low-speed C-D road entrance terminals. The high-speed collector-distributor entrance terminal is intended for use on rural inter­state highways and other freeways where high-speed design has been designated. The low-speed collector-distributor entrance terminal is intended for use on all other freeways. Three exit terminal lane conditions are shown on Fig. 2.45b. These terminal designs are to be applied to highways using either high-speed or low-speed terminals.

Superelevation at C-D terminals should be developed similar to that prescribed for standard ramp terminals.

Foundation wall insulation

Posted by on 13/ 11/ 15

Foundation insulation isn’t used in mild cli­mates. But in areas with frigid winter months, il uni improve interior comfort and save on heating costs. Even though it’s not required by code in many areas, it’s definitely worth installing wherever prolonged freezing tem­peratures are expected. You can install insula­tion on the inside or outside of a crawl space or basement wall. Exterior insulation, in the form of rigid foam boards, is glued to the foundation walls before backfilling. Where they’re exposed above the finished grade on the exterior, insulation boards must be pro­tected with siding material or stucco. It’s important to remember that ary type of foun­dation insulation can provide a hidden pas­sageway for termites and other insects to enter the house. Make sure you cut off this passage­way bv installing a termite shield beneath the sill. As shown in the illustrations on pp. 46-47, the shield should be installed between the top of the foundation and the sill.

Drainage around the foundation

After you’ve taken care of the details men-

#

tionedabove, you can begin backfilling around the foundation. Along the looting, install perforated drainpipes in a bed of gravel several inches thick. Cover the pipe with at least several more inches of gravel. To prevent
the drainage channel from silting up, cover the top layer of gravel with filter fabric before backfilling it with soil.