Here in the UK the deemed to satisfy requirements for raft foundations in clay soils near trees require a considerable amount of fill under the raft (about 1m in my case). It also requires a considerable “skirt” of fill material around the raft. The logic is that you are taking the bearing...
I am designing a timber frame house (in the UK). It is a particular system designed for minimum cold bridging for Passivhaus performance as shown in the image below using wide flanged wall studs and rafters connected with ply plates at the eaves and ridge. They form portals but are nowhere near...
I am having a few issues working out the capacity of fixings for a heavy cast iron cladding system to some lightweight steel stud framing. The studs are 150x50x1.2mm lipped channel sections. They are clad in 12mm of gypsum board. Then we fix a stainless steel Z-rail through this to carry the...
I have been asked to assess the structure for a temporary 12m high steel sculpture which is basically the outline of a person using heavy 260x260mm I sections cantilevering out of concrete base. The I sections face out from the person with their weak axis. It is in an exposed location so I get...
Apologies for any terminology errors here and I am in the UK so it may differ from the US but the attached diagram should help. I am looking to justify the capacity of screws through a 45mm thick LVL ledger beam (supporting floor joists) to a rim beam spaced apart by 12mm OSB and 25mm battens. I...
We are putting a new hole through a composite RC slab on metal decking adjacent to an existing composite steel beam. The hole is within the effective concrete flange width but not right next to the beam. I can frame the hole with new non-composite steel members but I can't find any guidance on...
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...
We are proposing using contiguous 300mm dia pile walls for a domestic basement in clay where the ground water level is below the basement level generally. However, the basement obviously needs to be designed for a higher water level. I assume that in the permanent case the piles could be...
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...
In BS5950-3 there is a limitation on the minimum number of shear studs allowed being 40% of the amount required for full plastic shear connection. I believe AISC has a similar limitation. I am checking a building we are doing alterations on and I have only 30% of studs required for full shear...
I am trying to do a detail for the fixing of handrail posts to steel beams. How would you determine how far down the web of the beam to put the stiffener plate for a side fixing to the beam? Also when fixing to the top flange of the beam and fixing to one side of the flange I would have thought...
I have a situation where I have very large windloads on metal sheeting. For the IBR sheeting I have always used the manufacturers tables of purlin spacing previously. However, they have a limit on the windloads and my loads in this case are far in excess of those limits. Has anyone worked out...
Rather than hijacking the other thread on this I have another hook/ development question. At the top of an external column of a concrete moment frame you get a top bar that needs anchorage into the column. I am taking the standard hook and anchoring that into the outside of the column. Then I...
I am wondering about the design of standard steel end plate and cleat connections for simple construction. I understand that the connections are designed to allow rotation of the beam ends and this principally happens by flexing of the end plates at the top of the connection between bolts. Hence...
I have seen this question come around a few times but never seen a convincing answer. How do you reinforce the top corner of an RC moment frame. I think that the outside column bars should go over and lap with the top roof beam bars to take care of the moment. When you see details they tend to...
I have been trying to locate specific design guidance on open frame industrial structures and haven't found much. I got the ASCE publication on wind loads and anchor bolt design which is very useful but nothing more. Infuriatingly I find references all over the internet to another ASCE...
I am looking at an industrial steel structure. It is relatively small - 3 levels of steel on a concrete platform with a footprint of 12m x 6m. I have modeled it and want to look at the thermal effects. When I put in a 60 degree temp change I get huge forces. I wasn't expecting those kind of...
Using the British standard, columns in simple braced construction need to be designed for eccentricities of load from attached beams of 100mm from the face or the web. What eccentricities do others use? In my particular case I have 2no. 800mm deep plate girders framing into the top of a corner...
I have a load factor question. I am doing pile design and geotech have given me an allowable pile service load based on an FOS of 3. However, they say this can be reduced to 2.5 for the transient portion of the load e.g. wind and earthquake. For wind there is no problem but ASCE also allows...
Is there not an inherent contradiction within ASCE 7 in that to calculate ELFs you use a seismic weight with only 25% of LL but then when you combine load factors you use up to 0.75LL for allowable stress design. So you are combining ELFs based on 0.25LL with gravity loads of 0.75LL?
