I noticed in the webinar videos the beams between lateral frames are assigned to "gravity". Am I wrong thinking these beams should be "lateral" since they will act as a drag member to get load from the diaphragm to to lateral frames?
Variations of this discussion have occurred here before. My particular case falls within exceptions where I can use R=6.5 for shear walls and R=3.5 for the OMF (rather than 3.5 for everything). That makes me happy. I wanted to be sure I am reading exception 3 of 12.2.3.3 of ASCE 7-10 correct. If...
I'm curious on opinions about using FE analysis for unusual steel connections. More specifically, using plate/shell/solid elements to model a connection that doesn't fit into anything in AISC.
Do you ever do it?
Do you just look at stresses?
Do you accompany with some hand calcs to check plate...
Hello all,
I am trying to model a steel frame with a wood shear wall which seems like an easy enough task. The columns are pinned at the base and the beam is simply supported. When the shearwall fills the entire frame everything is dandy. When the shearwall only fills a portion of the frame Risa...
I have a case where we have a steel frame and need to use wood shearwalls for the lateral load. Is is possible to stop the wood wall from taking vertical load from the steel beam above? Do I have to do something like add a bunch of shear only links to connect the wall to the beam?
I am using a number of rigid links in a model. The links need a to be fixed at one and and fully released at the other. When I release one end and run the model they are deflection about 550 inches. Any tips here?
Does RISA have a way to modify the properties/stiffness of elements? For instance, I need a plate that is calibrated to data. To do this I need to apply and adjustment to to some of the bending and mass properties.
Also, can different thicknesses be applied to membrane and plate bending?
I am...
Risa always assumes vertically spanning walls in the design it seems. Even the regions above and below the openings span vertically. I realize this is possible to some extent due to the boundary conditions but what about the fact that in a masonry or concrete wall many times you cant actually...
I am new to risa and risafloor. I am modeling a CMU building in risafloor that has three roof elevations (approx 11', 12.5' and 22'). I created a floor plan for each elevation and put in my walls. Now I am putting in all my openings and have hit a problem. In the tall portion of the building I...
I was wondering what you are all doing when you design a deck as a cantilevered horizontal diaphragm but using composite decking? The ESR report for Trex specifically says it may not be used as a diaphragm (section 5.1). Am I misinterpreting the ESR report when it states "Trex must not be used...
In Terry Malone's book "The Analysis of Irregular Shaped Structures" he analyses a shearwall using a veirendeel truss analogy (method originally from ATC 7 but adapted to shearwalls). He shows the results in the figure below:
Being a book focused on analysis he makes mention of a few design...
I was wanting to add a bit more automation to some of my wind loading (envelope method) spreadsheets but I REALLY don't feel like doing all the data entry for the Ps30 tables. Has anyone done this and willing to share?
I have been attempting to model a cylindrical shell in sap2000. I have gotten good results compared to Roak's for some of the load cases I am looking at. One that seems to be giving me grief are the results from an applied surface pressure. I have applied a pressure of 160 psf normal to the top...
Hello,
I have recently been playing with Calculix a bit and have found it pretty useful. I have generated a model of an annular section that is quite thick (66"OD 24" ID 13" T) and was hoping to compare the radial and tangential moments to those calculated using Roark's equations (I wanted to...
We recieved an RFI stating that due to material availability a shop splice will be required for a W33x201 we speced. The fabricator said the splice is to be a complete-joint-penetration weld and weld access holes filled, all to be tested with ultrasonic testing.
My manager wants to aswer the...
I have a quick one (yes I am new to the job). I am reviewing some shop drawings for rebar and the bending detail schedule had dimensions (which are probably some standard I dont know about) that I dont understand. It has lengths like "1-111" and "0-08".
Teach me sumtin!
I have an interesting problem which is fairly basic but not something we are required to think about too often and I may therefore be oversimplifying it.
I guess some fabricator needs to bend a 1 1/2" dia. A36 bar (not rebar). The bend is 90*. The fabricator is not sure his machine can do it...
Hello all,
I am a pretty new to the professional world and although I have a masters I have done/seen very little footing design. I was wondering if you guys could suggest any good books that focus on "our" design concerns as structural designers.
I have a problem with a GUI I have been working on (generated with GUIDE). In one function I assign a value to a variable and then put it in the handles structure and update it...
units_x = 'in';
handles.units_x = units_x;
guidata(hObject, handles);
but when I try and use handles.units_x...
