I'm modeling a continuous beam that has 5 spans and the end spans are cantilevers. When all of the spans are equal, the moment at the first supports from the ends from Risa are correct. That is they match the moments calculated using structural analysis; w(l^2)/2.
When the end spans don't equal...
I am using Bentley's Conspan to design a voided slab superstructure. I am trying to find out why the Service I self-weight deflection doesn't match the deflection due to the self-weight load case, or my hand calculation.'there should be no factors applied for Service I. I have stripped off all...
I am looking for a very good shop capable of high end fabrication of stainless steel architectural metal work. Five-axis cnc type of work. Any suggestions on where to look?
Thanks
I am analyzing a table for a friend that has a base made of 3/4" diam. steel bars, with a 1" thick glass top. The base consists of one piece of bar that has many 90 degree bends, and stability may be an issue. Risa 3D and other programs can do this, but I was wondering if there is software out...
I am trying to understand the provisions of ACI Appendix D (318-08), specifically Section D.6.2.9 on anchor confinement reinforcing. To me, the code doesn't specifically state how to design the confinement steel, but states the steel must be developed in accordance with Chpt 12.
I checked in...
I am determining the base shear for a single story structure and someone told me that I shouldn't include the parallel wall weights in this.
I also read in the Structural Engineering Reference Manual, 4th edition, Diaphragm Load Section that the seismic weight tributary to a diaphragm should not...
I am designing OMF connections using the Seismic Design Manual, for an R > 3. The thing I'm confused about is the required shear. Section 11.2a of the Provisions states Vu or Va must be increased by the seismic load effect, E = 2[1.1RyMp]. Page 4-3 of the Manual shows the same value but in the...
I've been designing some cmu lintels and some configurations I need are not in Table 4 of TEK 17-1B. I created a spreadsheet to design my lintels and checked it against the Table 4 values. What is strange is some Mresisting values match and others are off by a significant amount, say...
Can someone tell me why RAM computes a negative moment capacity for a beam using the composite properties? I checked the documentation and it does use the composite properties if the moment isn't greater than 2x the positive moment.
Unless I'm missing something, the code states that the...
I have a model with multiple diaphragms at different levels, but also at different locations in plan; it is an "L" shaped structure. With the various stories, I have columns that RAM treats as segmented at the different story locations. The problem is the little segmented column masses are not...
I am using v11.2 and am having trouble with the redundancy factors for seismic analysis. I manually input the rho values as 1.0 in the load combination generator, as my project is SDC B. However, when I check the output it lists varying values of rho, typically 1.5. I checked the Manager Default...
I am designing a below grade concrete culvert. My question may be dumb, but the way the IBC states to distribute the load seems unconservative. Also, IBC refers to AASHTO, but I thought AASHTO specified a 32 kip pt load.
Essentially I'm modeling a 1' wide strip of my box culvert structure...
I am modeling a structure with unreinforced brick masonry walls and concrete diaphram, with both axial and lateral applied loads. It is a narrow structure and I am trying to accurately determine the restraint of out-of-plane drift provided by the wall bases. I have to assume there is no dowels...
I am designing column baseplates using Risa Base (FE element software). I recently attended a webinar from Risa on this software. The presenter suggested not checking the "force baseplate to be rigid" box saying it may not be conservative. The anchor tension values you get from assuming rigid...
I am working on a project where we have to analyze an existing outdoor plaza, that does not have vehicular loads.
I'm not sure what category this falls within. I actually thing the appropriate code is the relatively new ASCE 31. Any suggestions?
I am trying to use the torsional stresses reported by Risa to compare to the AISC Design Guide #9 Example 5.1 for checking torsion. It seems the warping stresses reported by Risa are reverse of what I should be seeing at midspan. Risa shows the max warping stress (for top and bottom) at beam...
I have created a 3D model of a concrete structure and used plates for walls and slabs. I have had trouble when meshing a wall that is connected to a slab I already meshed. Using the auto mesh tool, Risa does not recognize the existing joints along the common edge and I have to go in and manually...
I have a project where the special inspector flagged some welds because they were done with GMAW process. The welds are 3/16" vertical fillet welds. Is this procedure pre-qualified for this type of weld?
