Dear all
I am trying to simply compute the natural frequencies of a 4 storey structure in ETABS. I am also trying to validate them in MATLAB. However, I am getting drastic differences in the results. This is strange because a couple of years ago I did a dynamics of structures coursework...
Hi all,
I have download the 30 day trial for ETABS and practising with it.
I am trying to find the storey stiffness in my model. To do this you go to Tables > Analysis Results > Structure Output > Other Output Items >Story Stiffness. However, the table comes out completely blank, as you can...
Hi,
I have the following example where by I am trying to calculate the axial force in the tie beam:
The geometry is: width = 10m, height = 8 metres, angle = 57.995 degrees. The diagonal members are 9.43m (sqrt(89))
And these are the support reactions:
If the tie beam is fully fixed I can...
Dear all
I have this simple structure in SAP2000:
I want the self-weight of the slab to transfer to the beam at the slab edges. The self-weight = 25 kN/m^3*0.2m = 5 kN/m^2. I have done the appropriate meshing, but the self-weight of the slab does no seem to be transferring to the beams...
Dear all,
I have the following structure with its loading that I am trying to solve
I am using the stiffness method, and my MATLAB code is below:
clear, clc, close all
% Structural properties
E = 2.1E+08;
I = 1022000/100^4;
A = 620/100^2;
EI = E*I
EA = E*A
alpha = atand(30/40)
L1 = 10;
L2...
Dear all
I am currently working on a hypothetical project for the following structure:
Firstly, I am tackling the load distrubtion on beams in kN/m from an applied area load in kN/m^2. I am analysing the load that comes from the floors including the imposed load which is 2.95 kN/m^2. You can...
Hi there, everyone,
I have been working on a problem in which I would like to calculate the load shares and deflections of structural elements in a multi-storey building. These elements include moment-resisting rigid frames, diagonally braced frames, concrete cores, and shear walls.
Thus far...
Hi there,
I was wondering if someone might know why I am getting incorrect signs for my structure that I am working on using the Direct Stiffness Method? I am following the procedure that I was taught when I was at University and I can't completely remember everything. I am designing a...
Hi all
I have been learning the shooting method for boundary value problems. For second order differential equations, as you may well know, you need two initial conditions to get the procedure going; one known condition and one guess. I am using eulers method, so I am reducing the second order...
Hi there,
I am trying to use approximate methods to solve for a multi storey rigid frame, and I am going through an old CTBUH book from 1979 that has much interesting informmation on structural analysis on tall steel buildings.
I have been desatisfied with the portal method, cantilever method...
Hi there,
I am making a design method statement for the installation of soldier piles/king posts and lagging to support an excavation. However, I am unsure of the safe distances between the mobile plant that work togther in unison to complete the job. The mobile plant includes a drilling rig...
Hi all,
I am wondering if anyone on here has experience with Tekla Structural designer and knows how to switch between one way and two way load distribution? Because I have panels in my structure with area loads and the load is going only one way even though the dimensions are such that the...
Hi there everyone,
I have a couple of books by Stafford Smith and Coull (Tall Building Structures) and Zalka (Structural Analysis of Multi Storey Buildings) which present some approximate methods to use to compute horizontal deflections of tall buildings under horizontal loads. However, for me...
Hi guys,
Back again!
I am attempting to solve a pinned support gable frame using the unit load method.
I am using BeamGuru software, but I want to check the results to esure the program is working properly.
I have replaced the pinned supporta at A with a roller and it looks like this:
The...
Hi all,
I am trying to solve for a gable frame using the Direct Stiffness Method. The frame is obviously constructed of two rafters and two columns. I am quite confused: I am getting the correct results for the columns, but not for the rafters. I am comparing my results to those in ETABS for...
Hi all,
If I have a basic gable frame such as the one below that has a wind pressure acting on it (say 1 kN/m^2). What is the best way to distribute this pressure to the columns and rafters as UDL's in kN/m? The pitced roof section is giving me a bit of a headache. Im not sure how to apply the...
Hi all,
I am trying to solve the following Portal Frame:
I am using BeamGuru to validate my hand calcs and they give the respective moments that are shown in the image.
The dimensions are: columns 5 metres high, and rafters that are 8.2462 metres long. The frame is 16 metres long (8 metres...
Hi there,
I am trying to solve a rigid frame that is supported by two pin supports. I am doing this using the unit load (or virtual work) method. To do this I am trying to create moment functions for each segement of the frame.
This is what my frame looks like:
I have replaced the pin...
Hi there guys,
I am working on a problem that is a 3 storey rigid frame structure using the Stiffness Method. I have checked and checked it and there seems to be nothing wrong with it. However, I am getting incorrect values for the moments at the nodes. I am comparing my code with SAP2000, and...
Hi there,
I am creating a portal frame model in SAP2000, and I am applying a UDL upon one of the rafters as shown below.
I am also using the stiffness method in MATLAB to validate my results from SAP2000. Thus far, I only have experience for models with orthogonal members and I am stuck on...
