Hello,
I am currently designing concrete drilled piers, and per the geotech report, the recommendations incur a 1600 psf design stress for potential frost heave. The recommendations also state that placing friction reducing material can be considered as an alternate option to prevent damage...
Hello,
I am designing a substation support structure, and I was wondering if anybody had any guidance or experience with orthogonal combination of seismic loads when using the Equivalent Lateral Force procedure. Per ASCE 113, Section 3.1.7.8, it states a series of design load combinations using...
Hello,
I am designing an exterior steel stair and was looking to implement bar grating treads with end carrier plates containing holes for 3/8" bolts. I know I am dealing with very little load, but I am wondering if others have specified a 3/8" hot-dipped galvanized bolt in the past? What grade...
Hello,
I am working on a WF beam to HSS column connection that I am hoping to achieve through a WT element. My question is with regards to whether it is reasonable to assume this connection to be "pinned." The connection is subject to axial force, vertical shear force, and horizontal...
I have a question regarding lateral pile analysis that I am trying to wrap my head around.
I have an analysis of a single drilled shaft that I am working on using LPile. I performed a pushover analysis to see at what level of pile head displacement that a plastic hinge would develop in the...
Hello,
I have posted about this before, but had to make some design changes. I have a concrete strut (primarily an axial member and taking small flexural demand) which needs to be shifted up towards the top the wall it connects to. I have the following questions:
1. For this strut to behave as...
Hello,
I am designing a strut between two retaining wall structures for reasons I won't get into in this post. My question is the following: The beam end will have some fixity at the wall interface. However, I am wondering if a conventionally reinforced wall will be able to resist that moment...
Hello,
For a plate analysis, is there ever a scenario where you would sum the out-of-plane transverse shears Qx and Qy? I believe the answer to this question is "no", but I am confused at what occurs at the corner of the plate where the shear forces "intersect".
Hello,
I am working on a complicated retaining wall structure for a Bioretention area. I have modeled the structure using plates in RISA-3D. Given the lengths of the walls, I have chosen to implement a strut between walls to relieve the flexural demands on the walls resisting the lateral earth...
Hello,
I am working on a project in which there is a proposed penthouse (CFSF framed) being built on top of an existing roof structure of a two-story building. The penthouse walls actually coincide with 24 ft long existing concrete load bearing walls below, constituting a square core in the...
Hello,
I have a really difficult connection to detail here, and I am about out of ideas. I am trying to resupport existing steel roof deck (H.H. Robertson Type DC) on a brand new collector beam at the interface of an existing building and new building expansion. I want the connection to be able...
Hello,
I am trying to justify a one-way slab for loading imposed by new electrical equipment. I know the weight of the equipment. Has anybody ever used a reduced load factor of 1.2 or 1.0 when checking the slab? Or should I treat the equipment as a DL at which point the 1.4DL combination would...
Hello,
I was given a soils report for a project I am working on which stated that for sliding checks of footings, the friction factor given should be multiplied by the dead load to obtain my sliding resistance. Does anybody else use only the dead load when checking sliding resistance? It seems...
Hello,
I am working on a project in which I need to reinforce an existing concrete spandrel beam for positive moment and shear. Interestingly enough, the amount of negative moment reinforcement is adequate. However, in looking at the bar lengths and bar bend diagrams provided on a typical...
Hello,
I am performing a mat foundation design using RISAFoundation. This "mat" is essentially a thickened concrete slab near grade elevation to support a heavy, long folding door for an airport hanger. The geotechnical report provided a subgrade modulus as well as a net allowable bearing...
Anybody have recommendations for the base of a CMU wall partition to a slab on steel floor deck connection? I have 2” composite deck + 3 1/4” LW concrete. I am thinking of embedding the vert bars 2.5” into the slab below with HY200 adhesive but not sure if there is a better option.
Hello,
I am wondering if anybody sees an issue with a detail I am working on currently. I have a condition where the client wants to raise, locally, the height of a parapet several feet to match the height of an adjacent parapet wall constructed out of 3-wythes of brick (The existing building...
Hello,
I have designed a grade beam and pile cap foundation system and am wondering how you guys generally address the issue of top and bottom rebar in the beams/caps from clashing with each other. Do you adjust the cover on the members? Or do you expect the fabricator to slightly bend the bars...
Hello,
I am checking a one-way slab for flexure, and I am hovering around capacity based on the loads applied. For the attached image, my question is, can I use the span length indicated as "l_e"? The slab is slightly overstressed when considering the center to center span, but it checks out...
Hello,
Say I have a 5 ft parapet for a building with an effective wind area of 8.33 sf. Per section 30.8 of ASCE7-16, there are two load cases for calculating the C&C wind loads on the parapet. If we take load case A, for example, would I essentially enter into the applicable figures for wall...
