Don't Assume, Design!
Third day at work, the job itself have progressed nicely from yesterday. Nice learning curve, smooth but enough to kept me on edge. Same problem to solve: design a lintel which will support the weight of the bricks above, instead this time a simply-supported reinforced concrete beam will be used. Very straight forward but a chance for me to experience an alternative design and different document set.
My support was amazing, very patience, confident and all-knowing, strict Muslim who prays five times a day, good honest bloke! I must have learnt more from him in one day than I have from my lecturer of the concrete module in a one month! Although there was this rather weird look in his eyes when I asked him about having to pray in the direction of Mecca. I think I saw the same look before when I have shown a slight interest in Islam to my friend who later tried to convert me. Oh well. I will never make a good Muslim. I drink, I smoke and quitting pork would mean I won't be able to eat half the food my parents cook.
The process was so much simpler compare to when I first learnt it. Same as the process in the steel lintel, there is a loading due to the Load Triangle plus any additional attachments within the Load Triangle and 50% attachment contribution from within the Interaction Zone. The moment and shear imposed can be deduced from the point load or UDL (wL^2)/8 wL/2. Decide on an appropriate design and then calculate to see if such configuration will satisfy the required moment and shear: Work out the effective depth (d), determine K and then K' based on the redistribution factor. Choose the correct equation to work out the moment capacity based on the two Ks relationship. The necessity of shear links can be determined by working out the shear resistance of the beam + bars. If shear links are required then another equation can be used.
It is important to note that:
1/ The links can not be placed at the end of the re-bars;
2/ Even though compressive bars are not needs, they are often added so shear links can be installed;
3/ Shear links are included for safety issue even though the values suggests otherwise (shear stress<0.5 shear resistance of reinforced beam).
The highlight of my day - My support: "You are a designer now, you don't assume, you design!"
My support was amazing, very patience, confident and all-knowing, strict Muslim who prays five times a day, good honest bloke! I must have learnt more from him in one day than I have from my lecturer of the concrete module in a one month! Although there was this rather weird look in his eyes when I asked him about having to pray in the direction of Mecca. I think I saw the same look before when I have shown a slight interest in Islam to my friend who later tried to convert me. Oh well. I will never make a good Muslim. I drink, I smoke and quitting pork would mean I won't be able to eat half the food my parents cook.
The process was so much simpler compare to when I first learnt it. Same as the process in the steel lintel, there is a loading due to the Load Triangle plus any additional attachments within the Load Triangle and 50% attachment contribution from within the Interaction Zone. The moment and shear imposed can be deduced from the point load or UDL (wL^2)/8 wL/2. Decide on an appropriate design and then calculate to see if such configuration will satisfy the required moment and shear: Work out the effective depth (d), determine K and then K' based on the redistribution factor. Choose the correct equation to work out the moment capacity based on the two Ks relationship. The necessity of shear links can be determined by working out the shear resistance of the beam + bars. If shear links are required then another equation can be used.
It is important to note that:
1/ The links can not be placed at the end of the re-bars;
2/ Even though compressive bars are not needs, they are often added so shear links can be installed;
3/ Shear links are included for safety issue even though the values suggests otherwise (shear stress<0.5 shear resistance of reinforced beam).
The highlight of my day - My support: "You are a designer now, you don't assume, you design!"
Labels: Civil Engineering, lintel, reinforced concrete beam
posted by Twisted @ 20:53:00
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