Timber

T I M B E R

As Structural Material

Parts of the tree which are used for Structural Timber

Workers chop down trees for heat or structure

Early logging companies used to chop and float logs

Entire swaths of forested land were clearedToday, logging companies

cut and replant

Timber-is wood that is at any stage between its felling and readiness for use as a structural material for construction or wood pulp for paper production

• housing • commercial buildings• although most industrial buildings

are composed of either prefabricated steel or concrete, wood can be used to fit out the interior offices, build stairs and platforms, etc.

Today, the use of timber can be found in a variety of applications:

• Timber is used in loadbearing-wall structures both as the horizontal elements in masonry buildings and in all timber configurations in which vertical timber elements are spaced close together to form wall panels.

Two Types of Timber Products:

• ALTERNATIVE TIMBERS- remanufactured timbers

• CONVENTIONAL WOODS- genuine timber

1. Plastic Timber

-isn’t wood at all, but a 100 per cent recyclable material that is made of recycled plastic made to look like genuine wood

Alternative Timber Examples

2. Fibre-reinforced composite timber -involves a complex mix of refined, blended and compounded natural fibres -makes use of rice husk, rice hull and plastic-actually hollow


2. Wood-plastic composites- made of:* wood fibres* wood flour * thermoplastics

-Cannot be recycled


Trees grow in all shapes and sizes, and of course they come in countless different species. Even among similar types, they all have unique knots and imperfections and vary considerably in strength, utility and value – which is why timber comes in different grades suitable for distinct purposes.

Conventional Woods

• The I-beam with the plywood web (b) and the laminated beam (c) are examples of manufactured timber products. These normally have better technical properties than plain sawn timber elements such as that shown in (a).

• Should have uniform color and regular annual rings.

• Should have straight fibers.• Should be sweet to smell when

freshly cut. A disagreeable smell indicates decay in timber.

• Should be sonorous.

Requirements of a Good Timber

• Should be free from natural defects.

• Should not be affected by fungi and other insects.

• Should have firm adhesion of fibres.

• Should be durable to resist the atmospheric effects.


• Should be tough to resist the shocks.

• Should not be split when nail is driven into it.

• Should be well seasoned.


• A condition in which timber shrinks following a reduction in moisture content due to decreasing relative humidity and swells if the moisture content increases.

MOISTURE MOVEMENT

• It is a process in which the timber must be physically restrained to prevent the introduction of permanent twists and other distortions

SEASONING

ADVANTAGES and

DISADVANTAGESTIMBER

• Timber provides for flexibility of design, and allows modifications and tweaks to layout during the construction process.

• Wood is a lower cost raw material than steel.

• In solid form, wood also has significant thermal mass properties, retaining heat from the day and releasing it at night.

ADVANTAGES

• Wood also acts as a humidity regulator, absorbing moisture when humid and desorbing moisture when the air is dry.

• Wood doesn’t rust.• Quick construction times. Builders are

familiar with using wood, and usually prefer it. Builders report frame construction times of two to two and a half times longer for steel frames.

ADVANTAGES

• Wood treated with the appropriate level of preservative, and properly maintained, can last in service for a hundred years or more.

• Recyclable, renewable and sustainable• Wood is a decorative material when

considered as an aesthetic material.• It is easy to repair and maintain wood.

ADVANTAGES

• Susceptibility to decay of timber when exposed to excessive moisture.

Wood is a hygroscopic material. This means that it will adsorb surrounding condensable vapors and loses moisture to air below the fiber saturation point.

The agents causing the deterioration and destruction of wood fall into two categories: Biotic (biological) and abiotic (non-biological). Biotic agents include decay and molds, fungi, bacteria and insects. Abiotic agents include sun, wind, water, certain chemicals and fire.

DISADVANTAGES

• Additional design and engineering time.• Combustibility of timber requires

vigilant quality control to achieve required fire rating of separating and compartment walls.

• Transport from resources.

DISADVANTAGES

EXAMPLESTIMBER

Center Pompidou - MetzBy Shigeru Ban Architects Europe

The wooden observation tower at Helsinki Zoo in Finland was the winning design in a competition held for architectural students of Helsinki University of Technology. Situated on a small island just outside the city, and built on one of its highest hills, it provides visitors to the zoo with panoramic views over the sea and surrounding area. LUSAS Civil & Structural was used in the design and analysis to prove the safety and structural behaviour under imposed loading.

Wooden Tower, Helsinki ZooBy the Architectural Students of Helsinki University of Technology.

Yusuhara Wooden Bridge Museum, Takaoka-gun, Kochi Prefecture, Japanby Kengo Kuma & Associates

Richmond Olympic Oval British Columbia, Canada

Sneek, The Netherlands. Heavy-traffic Accoya Glulam Bridge

THANK YOU FOR WATCHING!Group Members:ROSALES, Mark ChristianAUXTERO, Ivy D.BALTAZAR, Pauline Camille G.PACHAO, Debbie Hope B.

REFERENCES:

http://dab510-2014-patricia.blogspot.com/2014/04/project-research-timber-structure.html

http://www.lusas.com/case/civil/wooden_tower.html

http://www.archdaily.com/199906/yusuhara-wooden-bridge-museum-kengo-kuma-associates/

http://en.wikipedia.org/wiki/Glued_laminated_timber

http://www.constructioninfocus.com.au/index.php/2013/05/15/a-brief-history-of-timber/

Structure and Architecture 2nd Edition

A PARTIAL REQUIREMENT ON AR 425-B ARCHITECTURAL STRUCTURES

INTSTRUCTOR: ARCH. HENRY C. DESIERTO

Education

Timber