Blog Archives

BOLSTERING JOISTS

Posted by on 16/ 11/ 15

Widespread sagging or excessive springiness in a floor is probably caused by joists that are too small for the span or by post, pad, and founda­tion failure, as covered in Chapter 10. Isolated joist failure is usually caused by insect or water damage; an earlier renovator cutting into the joist; or point loading, in which a heavy piece of furniture or a tub causes joists to sag. If there’s infestation or rot, correct that condition first.

Sistered joists. The most common way to rein­force a weakened joist is to nail a new one to it— a “sister” of the same dimension and length. The new sister needn’t be the exact length of the origi­nal but should be long enough to be supported on both ends by the perimeter foundation or a girder...

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CONTINUITY AND JOINTLESS BRIDGES

Posted by on 16/ 11/ 15

Where possible, bridges should be made continuous. Continuous spans are less prone to catastrophic collapse from loss of substructure support due to stream erosion, earth­quake, or vehicle or vessel collision. Bridges with multiple simple spans must have two lines of bearings and an expansion joint at each intermediate support. Two lines of bearings, each having the required capacity for the end of a simple span, will almost certainly be more expensive than the single line of bearings required for con­tinuous spans. Expansion joints are expensive and in most geographic locations should be sealed against storm drainage and intrusion of debris, which further increases their cost. (Even the manufacturers of sealed expansion joints agree that the best joint is no joint...

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SHEAR WALL DESIGN CONSIDERATIONS

Posted by on 16/ 11/ 15

SHEAR WALL DESIGN CONSIDERATIONS

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11 11

 

PLywOOD FLOOR

diaphragm

 
SHEAR WALL DESIGN CONSIDERATIONS

SHEAR wALL SHEATHING LAPS RIM jOIST,

OR

FRAMING ANCHOR TIES DIAPHRAGM TO SHEAR wALL STRUT.

 

FOUNDATION

WALL OR FLOOR ; ! STRUCTURE

 

Double TOP PLATE ACTING AS A SHEAR wALL STRUT

 

SPECIAL ANCHOR BOLT EMBEDDED IN FOUNDATION AND/OR CARRIED THROUGH FLOOR STRUCTURE PER MANUFACTURER’S INSTRUCTIONS

 

SHEAR WALL/ROOF DIAPHRAGM

 

SHEAR WALL/ROOF DIAPHRAGM

 

SHEAR WALL DESIGN CONSIDERATIONSSHEAR WALL DESIGN CONSIDERATIONSSHEAR WALL DESIGN CONSIDERATIONSSHEAR WALL DESIGN CONSIDERATIONS

SHEAR WALL DESIGN CONSIDERATIONS

SHEAR WALL DESIGN CONSIDERATIONS

DIAPHRAGM

DRAG STRUT TIES MARGINAL PORTION OF DIAPHRAGM TO SHEAR WALL.

 

SHEAR WALL

 

SHEAR WALL DESIGN CONSIDERATIONS

SHEAR WALL DESIGN CONSIDERATIONS

When shear walls are required on upper floors, they must be tied, through the floor diaphragm, to the shear walls below...

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STEP 8 INSTALL AND PLUMB DOOR AND WINDOW TRIMMERS

Posted by on 16/ 11/ 15

Many builders—even experienced ones—don’t like to spend time plumbing window and door trimmers. But I’ve found that this step really makes a better building. If the door trimmers are plumb, the door’s hinge-side jamb butts solidly against the trimmer along its entire length. There’s no need for shims on this side of the door. That means you save time and obtain solid, continuous backing for the jamb that sup­ports the full weight of the door. If the opposite trimmer is also plumb, the shims you install can
share the same thickness. There’s no fussing to make shims of different sizes. Similarly, win­dow installation benefits from plumb trimmers.

Window trimmers were installed during step 5, when the window assemblies were built on the floor deck...

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Light Clay-Straw Construction

Posted by on 16/ 11/ 15

For construction in colder climates, where higher insulation values are required than can be provided by mud alone, several methods

that combine earth with lightweight natural aggregates have evolved. These include mixing mud with pumice, volcanic rock, straw, wood chips, expanded clay, or vermiculite. In the US, clay-straw construction has become the most well-known of these methods because of the work of Robert Laporte of the Econest Build­ing Company, who has taught workshops and built clay-straw structures throughout North America. The Laporte technique uses a light­

weight mixture of clay and straw as an “outsu – lating” wall around a timber-frame structure. Clay-straw can also be used as an infill mate­rial between deep structural members.

Straw is mixed with a clay slurry so ...

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Expansion Joint Sealers

Posted by on 16/ 11/ 15

Several types of expansion joint-sealing devices are available. Properly sized and installed, they can greatly reduce, if not eliminate, drainage through the joint. Some of the available types are

• Polymer-modified asphalt

• Compression seal

• Slab-type seal

• Strip seal

• Modular seal

Polymer-Modified Asphalt. For resurfacing projects where an asphalt concrete overlay or a portland cement concrete overlay is placed on an existing bridge deck, the approach slab is also overlaid, and the joint movement is moderate (no more than 1.5 in or 38 mm), an expansion joint seal using a poured liquid joint sealer and “armor” of polymer-modified asphalt concrete (elastomeric concrete) can be used...

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Step-By-Step Instructions

Posted by on 16/ 11/ 15

1) image41Buy your materials and order your windows. Be sure the trailer will accommodate the weight of your house. Cut any extra vertical parts off the trailer, but leave the wheel wells intact. Remove all the decking you can. Leave no more than 24” be­tween the remaining boards. These gaps should be cov­ered with aluminum flashing to guard against rodent and water infiltration. Do not put any beneath the porch.

2) image42Assemble the floor framing in front and in back of the wheel wells. Then connect the two sections by framing between the wells. Use screws instead of nails for this and all your fram­ing.

3) image43Fill the cavities with your choice of insulation (in this case, expanded polystyrene foam board with expanding spray foam at the seams)...

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SINGLE-WALL CONSTRUCTION

Posted by on 16/ 11/ 15

Structural Sheathing

SINGLE-WALL CONSTRUCTIONSINGLE-WALL CONSTRUCTION

SINGLE-WALL CONSTRUCTION

SINGLE-WALL CONSTRUCTION

Подпись: 8-Ft. Panel Typical8-Ft. Panel with Water Table

Подпись: NONSTRUCTURAL SHEATHING

Подпись: (A GYPSUM SHEATHING

SINGLE-WALL CONSTRUCTION

NON-STRUCTURAL

SHEATHING.

SINGLE-WALL CONSTRUCTION

FULL-SIZE PANELS (AFT. X 8FT., 9FT, OR 10FT.) CAN PROVIDE STRUCTURAL

sheathing and/or FIRE resistance.

Many sheet materials that can be used for sheathing do not provide adequate lateral bracing. In addition to providing a base for a moisture barrier and siding, such nonstructural sheathings may also provide insulation or fire protection.

Insulative sheathings range in thickness from V2 in. to 1У2 in. They include fiberboards, foam plastic, and rigid fiberglass boards. R-values vary. Verify that the permeability of the sheathing is coordinated with the permeability of the vapor retarder (see 88A).

Siding must be nailed throu...

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Expansion Joints

Posted by on 16/ 11/ 15

Bridge roadway expansion joints are provided to accommodate the thermal changes in the superstructure, and, in the case of prestressed-concrete bridges, to accommodate creep shortening of the superstructure as well. They are required at abutments that are restrained against longitudinal movement and at the end of supported superstructures free to translate due to provision of expansion bearings. In some long-span steel bridges, expansion joints and expansion bearings must also accommodate change of length of span due to live load deflections...

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Extrapolation problems

Posted by on 16/ 11/ 15

Most often frequency analysis is applied for the purpose of estimating the mag­nitude of truly rare events, e. g., a 100-year flood, on the basis of short data series. Viessman et al. (1977, pp. 175-176) note that “as a general rule, fre­quency analysis should be avoided… in estimating frequencies of expected hydrologic events greater than twice the record length.” This general rule is followed rarely because of the regulatory need to estimate the 100-year flood; e. g., the U. S. Water Resources Council (1967) gave its blessing to frequency analyses using as few as 10 years of peak flow data. In order to estimate the 100-year flood on the basis of a short record, the analyst must rely on extrap­olation, wherein a law valid inside a range of p is assumed to be valid outside of p...

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