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Joe, But, as DTs can move due to temperature change or applied dynamic loadings, this rigid restrained welding connection could cause failure around the connection rather than improved stability.

Generally, double tee and girder welding connection is not recommended.

Hello! Food processing facilities require special finish on concrete wall surfaces. Where can I obtain detailed information with respect to this issue? FDA? _JRW

The following info came from PCI committee's report, which I have edited as an example. Insulation walls can be used for both load bearing and non-load bearing walls. Composite action with shear connectors may allow this system applicable to high ceiling structures. I guess similar problems...

Aesur, I understand your questions and concerns. I think this area is really tiny niche market, but growing industry. PCI's committee report "State of the Art of Precast/Prestressed Concrete Sandwich Wall Panels, 2ned Ed." will provide general knowledge. -JRW

Hello! I am looking at 8" think precast prestressed concrete insulation wall design ONLY with strands and shear connectors. (No WWR or additional reinforcement except solid zone around stripping/handling anchors.) As strand layout was decided for the wide pieces with opening in the middle of...

Hi! I wonder this patch method with cement grout can be used to prevent corrosion issue in the food processing facilities. I saw this method in the precast concrete projects. Is it acceptable detail to avoid corrosion-related problems with black finish plates and angles? Thanks! _JRW

Hello! In order to check connection details during erection stage in the precast concrete beams, I am looking for a book or papers explaining how to predict section behaviors after prestressing force is applied. I am interested in horizontal deformation rather than vertical deflections/cambers...

Generally, 2% double tee slope is adopted due to floor drainage. On top of 2% drain slope, there should be 2"~3" camber due to pretensioning. So, it is hardly possible to satisfy 2% ADA floor slope requirement with pre-topped double tees. Should these double tees be field-topped, so topping...

Of course, intermediate posts should be added as required. (That topic is beyond this discussion.) Generally, vehicle impact and pedestrian fall protection should be considered simultaneously.

I have summarized my idea. I believe Method 1 is the most economical and safest method. Bending strand is not difficult with large bending radius and surface damage/scratch can be minimized with optimal installation process. (There is no reason to insert long cables starting and ending with the...

I think some accessories can be used to prevent elongation spread. Though very long single strand is used, that does not necessary to consider entire overall length to control/calculate elongation or strand stress.

Hello! I have a question related with barrier cable installation along the perimeter of parking structures. These barrier cables are required for vehicle and pedestrian fall protection. (My sketch does not show intermediate columns for the convenience.) In my opinion, one continuous stand can...

Generally, double tee stems are more critical than flanges structurally. Topping concrete will solve most crack related issues. I wonder what causes this problem. Either poor production technique, handling or torsion?

Examples of current PCI design handbook and my (old)steel textbooks use Fy=36ksi. I guess these examples are based on out-of-date market trend. I am raising this discrepancy between actual material and design calculation data as it can provide very conservative/unrealistic design experience.

Do you know what caused this change? Is it really difficult to see A37 in the market? A37 should be much easier to bend/cut and cheaper...

Hi! For precast concrete connection designs, generally A36 plates have been used. Recently, I was told A572 Gr.50 was more popular in the steel market. Is it true? Is it really difficult or no advantage to use A36 for connection design? (Including logistics and cost comparison?) When I...

It's not difficult to bend complicated shape with the automatic bending machine. As an example,

Seismic Design of Reinforced Concrete Buildings By Jack Moehle ...excellent, advanced level textbook!

I guess this is a kind of grey area and STM itself is too liberal... this topic is not clearly understood as a term 'disturbance' means. For example, the above reference used distributed load; no difference for concentrated load condition? Any data for pretension case like in the precast...