Sunday, June 28, 2009

anchor specifications



nowadays, there is a term used in the construction industry w/c is called " composite construction". wherein steel, wood, aluminum is connected to concrete. During our school years, we studied their composition, yielding capacity, strengths of various materials related to construction but sad to say, there is no subject about anchors. by the way, anchors is a way of fastening two different materials, i.e. steel to concrete, aluminum to concrete or wood to concrete. but since our topic is about anchor specifications we will dwell mainly into the fastening of steel to concrete.
Retrofitting is a term in w/c the existing structure is reinforced in order for it to make it stronger, sturdier. old buildings or new buildings w/c their structure is undersized or the design has been changed or modified has to be retrofitted so as to compensate the loads. typical example of an old building that needs to be retrofitted is to check their concrete slabs w/c are sagging due to wear and tear. the sagging of the concrete needs to be reinforced by a steel beam.
Building owners w/c have this problem go to contractors to repair their buildings. but contractors has to be sure if their retrofitting methods is safe. one way of addressing this to consult a "Structural Engineer".
Structural Engineers plays a big role in retrofitting methods because they are the guys who compute and design if the retrofitting method is suitable. one particular area the structural engineer has to consider is "Anchor Bolts". they have to know the technical data of the anchors involved so they can design it accurately.
After the design is finished and has a blueprint, the structural engineer inlcuded in its blueprint plan the anchor specifications w/c is to be followed. the contractor doing its retrofitting project has to work closely with the structural engineer in order to follow his specifications. Contractors not following the Structural engineers specs means the latter will not sign or approved the design. it will be at the contractor's risk if ever the structure will fail.
So anchor specifications are crucial in a new building construction or a retrofitting project. Building owners or contractors not following the anchor specifications because of price issues are inviting risks to themselves and to the property.

Wednesday, June 24, 2009

how to install expansion bolts

there are 2 types of anchors namely: mechanical anchors & chemical anchors. since our topic is how to install an expansion bolt, then let's dwell on the mechanical side.

instructions:

1. drill a hole into the concrete using a hammer drill. do not use impact drill or steel drill because it will take a while before you can make a hole. also, you have to exert extra strength and effort to push the drill. by the way, the drillbit should be the same diameter as the bolt.

2. clean the hole using steel brush and blow-out pump.

3. install the anchor and slightly hammer it with a hammer so it will fit in all the way.

4. tighten it.