We are looking at a contractor's method statement for needling an existing 327mm brick wall and he is proposing 203UC needles at 1m cc. The wall is 9.6m tall above the opening to be needled. That means that the stress in the bricks from the selfweight of the wall alone is 0.22N/mm2. For historic london brick construction the CIRIA guide allows a bearing stress of 0.42N/mm2. The wall is also carrying some load from floors so we end up with a brick stress of around 0.30N/mm2. So if the wall is to be needled, the needles would need to occupy more than half the area of the wall which seems a bit much. Even if we assume we can increase the bearing stress by the local factor of 1.5 to get 0.63N/mm2 allowable we would still need 203UC needles at 400mm centres which is way more than allowed for. What do temp works engineers normally allow for masonry bearing stress on needles?
Red Flag Submitted
Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action.
Reply To This Thread
Posting in the Eng-Tips forums is a member-only feature.
When was the last time you drove down the highway without seeing a commercial truck hauling goods?The ubiquity of these machines underscores the important roll they play in modern commerce. Download Now