Use the National Structural Code of the Philippines (NSCP) as a basis when designing vertical and horizontal structures (for structural design). This is almost the same with US' ACI (for concrete) and AISC (for steel).
Posted on: Mar 28, 2010, 11:55 AM
Speaking of masonry construction, the most common mistake of designers is that during the process of designing they are not considering masonry walls as structural elements. They only incorporate walls and partitions as an additional load for their structure, but during the actual construction it is very evident that these walls will be affecting the structural stability of a structure. It can add strength but it can also create an ill-designed structure. If we are not going to consider masonry walls as structural elements we should isolate the walls so it wont affect the movement of the structure.
Posted on: Mar 28, 2010, 11:56 AM
In the middle east they are only using the blocks as infill walls which is almost the same as architectural block construction. Although they are using stronger masonry blocks they are not really considered to give additional strength to their buildings. Another thing is, they are not really considering earthquake loads specially in GCC hence, assumptions of lateral movements are not that big (they only consider wind loads for small to medium-rise buildings). By the way GCC structural codes are almost based on British Standards.
Posted on: Mar 28, 2010, 11:59 AM
In my own honest opinion masonry infill walls with or without mortar is not really good for places with high seismic activities because the bonding of the walls and the reinforced concrete frame is not that sufficient. Due to insufficient bonding the walls and frame of the building may not move together and will not provide enough resitance for lateral loads thereby causing the infill masonry walls to collapse or sustain damages first because it is weaker than the reinforced concrete frame. By the way infill masonry walls are CHB walls installed after the frame of the buildings are constructed. In the middle east the are not provided with mortar.
Posted on: Mar 28, 2010, 12:18 PM
In the Philippines where strong earthquakes are very common, the best practice in constructing walls is the confined masonry system where masonry blocks are constructed first before the columns and beams (frame) of the structure. The bonding of the the frame and walls using this method is more sufficient specially if the masonry walls are reinforced, which means, horizontal and vertical reinforcing bars are provided to compensate the walls lack of flexural (bending) and shear strength. Of course there should be mortar fillers if you're going to provide reinforcements to ensure that the walls and reinforcements will act integrally.
Posted on: Mar 28, 2010, 12:43 PM
In our country the reinforcements and their spacing usually used are the following:
Vertical Bars (Usually 12mm diameter) - 40cm, 60cm and 80cm (maximum)
Horizontal Bars (Usually 10mm diameter) - @every 2 layers, @every 3 layers and @ every 4 layers (maximum)
Posted on: Mar 28, 2010, 12:43 PM
One thing that keeps me thinking is that in some countries where seismic activities are also high, confined masonry without reinforcements is sufficient and is accepted by the respective authorities. I'm not saying that we should follow this. Follow our codes, those are our guidelines. As the adage goes, "SO IT IS WRITTEN, SO IT SHALL BE DONE".
One more thing, do you know that with good engineering judgement you can produce on the back of an envelope that which otherwise cannot be produced with a ton of computer output?