Hello!
These questions are related with precast production efficiency and member design detail.
Double tee floors are sloped everywhere in the precast concrete parking structures;
let's assume 60ft long 12DT34 and typical floor slope 2% for drainage.
1. Is it really necessary to make double...
Hello!
Food processing facilities require special finish on concrete wall surfaces.
Where can I obtain detailed information with respect to this issue? FDA?
_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...
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...
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...
Hello!
I saw these two formula about internal stress of concrete/reinforcement from Dr. Moehle's
Seismic Design of Reinforced Buildings.
I could figure out (5.4), but I do not know how to derive (5.5).
Can anybody explain how to obtain (5.5) expression?
Thanks!
Hello!
GC plans to use telehandlers like Genie GTH-5519 to do CMU works over 12DT30 (4" thick flange).
How can I check they can use heavy equipment over precast double tees?
Its brochure shows weight (10.4Kips), Max lift capacity (5.5Kips), and wheel base (7'-6").
I need info about max...
Hello!
What's the difference between aircraft cables and prestressing strands?
For example, is there any reason to use 3/8" aircraft cables instead of 3/8" strands
to strip/handle precast concrete members?
Thank you very much for your interest!
_JRW
Hello!
Performance-base design concept was introduced to architecture study long time ago.
In fact, performance concept is one of hot topics in feminism also.
I wonder anybody can explain the history of concept/terminology 'performance'.
This concept has been impacting structural engineering...
Hi!
According to ACI318/437, the 24-hour load test procedure requires:
Test Load Magnitude: 1.15D+1.5L+0.4Lr/S/R, 1.15D+..., 1.3D
Acceptance Criteria: Max deflection is less than...
Residual deflection is less than max deflection/4.
I would like to know how/why these TLM...
Hello!
This is a typical detail used for the connection of precast concrete double tees.
I wonder if 3/8" loose plate should/can be galvanized.
In my opinion, this galvanized finish will be burnt completely due to high welding temperature
and relatively small plate size.
And, touchup finish...
Help!
Is there any method to pour self-consolidating concrete along the slope section?
Is this one of most difficult conundrums in the concrete industry?
... Nobody seems to know the solution.
_JRW
Hi!
I heard precast concrete stadium seats could be produced with self-consolidating concrete.
I wonder how they can be poured with different floor levels without cold joint
between first and second placement layers.
I am asking how I can make them monolithic concrete section with SCC.
-JRW
Hello!
Sometimes a lot of reinforcements can be concentrated at a section like precast columns with corbels taking heavy loads.
And then, can concentrated reinforcements cause brittle failure problem as wide continuous disruption surface can reduce
concrete monolithic property?
Can I ignore...
Hello!
To achieve monolithic concrete or composite action, generally “surface intentionally
roughened to an amplitude of 0.25 inches” is applied.
How can I make this surface preparation over green concrete in the precast concrete plant?
As a rake/rough broom has been used, it makes loose...
Hello!
Recently I found crack lines along the contact surface between concrete foundation
and soil around the stressing concrete block after prestressing force, 1000kips, was applied.
First I thought this was failure around prestressing beam line.
But, this could be elastic response of soil...
Hello!
Recently I have heard some steel fabricators say steel plates became warped
as they weld eight #8 rebars to 3/8"x8"x24"plate to make corbel plates for precast columns.
I did not hear this complaint before.
Is it due to poor welding skill?
Or, is it very hard to avoid warping problem...
Hello!
ACI 318-14, 12.5.1.5 says non-prestressing STRANDS can be used for diaphragm reinforcement.
Can we use non-prestressing strands instead of reinforcing bars for regular beams or slabs?
Many precasters dispose of tons of left over strands after producing girders and walls.
-JRW
