Ze Yang Lee's Activities

Class 4 Steel Section Capacities Eurocode

Ze Yang Lee — Tue, 18 Jul 2023 07:52:32 GMT

Does anyone know how STAAD derive the following for a Class 4 section?

- Minor axis bending moment capacity: if by multiplying elastic modulus with design strength, the moment capacity would be much higher than the computed values shown in STAAD output. Could it be possible that the effective area has been accounted?

- Why is there no difference between moment capacity and reduced moment capacity?

- Gross area equals to effective area? Why is it so? Class 4 section supposedly to be reduced according to EN 1993-1-1 and EN 1993-1-5.

Deconfinement vs Mstage

Ze Yang Lee — Thu, 18 May 2023 07:50:56 GMT

Hi guys,

Just wondering whether i) Mstage method or ii) deconfinement method to be adopted for NATM (taking steady state flow calculation into account)?

Modelling of connection between tunnel lining

Ze Yang Lee — Wed, 05 Aug 2020 04:20:50 GMT

Hi everyone,

I am modelling concrete tunnel rings with an opening. The rings are connected by shear dowels that supposed to have a shear capacity up to 300kN.

I have a few questions regarding the modelling technique of this structure. I have modelled a few rings (including the one with the opening). The purpose of this model, is to check whether with the opening, the opened ring and the adjacent rings are stable under the connection of shear dowels with the adjacent rings (whether the shear capacity is sufficient and will that induce too high shear stress in the concrete ring).

Due to the fact that, at the circumferential joints, the tunnel rings are connected by dowels and has some interfacial friction, I separate the rings by a small gap (0.05m) and I model a small beam to represent the dowel using steel with prismatic section (similar cross-sectional area to the actual dowel). The shear dowel is not supposed to have any bending moment in it, only shears. If I do not release the end moments, there will be bending moment in the beams but if I fully release the end moments of the beams, the beams are just like a flexible hinge, no restraining effect at all.

In Staad, is there any possibility to model such condition? I know we do not have any gap elements in STAAD. Although by right, there will not be any physical gap between the tunnel rings, but if we model the rings together like a monolithic tube with the opening, the behaviour would not be so right because the only way of shear transfer is through those shear dowels. If the shear exceeds the shear capacity, actually the shear dowel would fail.

Please see attached model below.

communities.bentley.com/.../tunnel-opening.STD

mesh and hole creation on curve plate (parametric model)

Ze Yang Lee — Tue, 22 Dec 2020 14:26:12 GMT

Hi guys,

I was trying to create hole on a curve plate. First of all, I have multiple nodes along the edges of the curvy side. Then, I choose parametric model, selecting all the nodes to create mesh but it seems like there is some problem in creating the mesh. Appreciate advice from the community!

Concrete Slab bearing on Steel Beams using STAAD.Pro V8i SELECTseries 6

Amir Kalasheh — Fri, 01 Jul 2016 00:44:17 GMT

I am trying to perform an analysis on an existing two-way concrete slab supported on each side by deep concrete grade beams using STAAD.

Background Info:

As part of a rehab project, a large section of the two-way slab needs to be cut-out and replaced; but the floor needs to remain operational during repairs. As such, steel beams will be placed directly underneath the bottom of the slab around the cut-out and connected to the deep concrete grade beams. In order to make the repairs easier and cheaper, the slab will sit directly on-top of the steel beams without any attachments between the two to resist negative (upward) bending of the slab.

STAAD Model Info:
I have modeled the concrete grade beams and the steel beams as well as 1'x1' plate elements (XZ Plane) representing the 12" thick slab. I used the offset command to set the top of the steel beams equal to the top of the concrete beams. Each beam has a node every 1' which sits directly underneath a corresponding plate/slab node. All of the slab/plate element nodes are 6" above the beam nodes in the Global Y direction to represent the center of slab elevation.

Is it possible to connect the concrete slab plate nodes to the steel beam nodes using the Master-Slave Command in the FY direction?

I am concerned about using this command because the slab is only bearing on the steel. I do not want the STAAD analysis to assume a composite connection with studs that would cause the steel beam to bend upwards with the slab in regions of negative moment. I only want the master-slave command to function in the (-)FY direction. Possible?

Would the appropriate master-slave command be RIGID to connect the existing slab which is doweled into the existing grade beams?

Modelling of slab supporting on piles

Ze Yang Lee — Tue, 14 Jul 2020 07:56:25 GMT

Hi guys,

I am modelling a slab supported on piles, the piles are actually tension piles to support upheave beneath the slab. I model the slab using plate elements and use vertical restraint node support at where the piles are located. The issue I am facing here is that, the out-of-plane shear will be very high, especially at those localized area and also closer to the edge of slab. I think that those shear is not realistic. I have read somewhere that, modelling some dummy members might help but I am not sure how to do it or if there is other methods to resolve this issue. There is no beams in the structure, only slab and piles. I have included a few snap shots of the loading conditions and out-of-plane shear results. I am pleased to attach my staad file here too. communities.bentley.com/.../1261.Launch-chamber.STD

Best regards,

Ze Yang Lee

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Tue, 14 Jul 2020 01:51:25 GMT

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STAAD Flat Slab

Saed Al-Halteh — Sun, 05 Apr 2020 09:49:15 GMT

I am modeling a Flat slab in STAAD.Pro , my question is do i have to connect the columns with the plates with a Dummy members ( as shown in image 2 ) or the connection as shown below (in image 1 ) is enough for the column to be as a support for the slab ?

image 1

image 2