concrete slab/beams with HS20-44 truck loads 2

[casasf]

I have not done this before but I have a condition that I ned to design a concrete slab (multiple spans)that spans between concrete beams spaced at 8.75'the length of the concrete beam is 59 feet. The beam frames into retaining walls One span condition) and continous over two supports.
Is there a software that someone can refer me to? Or are there any design aids/example that can be of help?

Thank you for your assistance in advance.

 

[MrHershey]

I've done something similar to this before in SAFE and RetainPro. Don't know if that's the best to use for it, but that's what I did. Experiment with multiple trucks in various locations to try and induce as much shear and moment as I can. Then get reactions out of SAFE and apply them to top of retaining wall. Though I didn't have the large concentrated load that you'll have with the beam reaction.

 

[bridgebuster]

If you're designing a slab - sounds like a bridge deck slab from your post - #5 at 6" top & bottom, perperndicular to traffic. If you're loading is HS-20, that's AASHTO Standard Specs; everything is spelled out in Chapter 3.

It's a simple design.

 

[casasf]

Thank you bridgebuster. I am getting thick slabs 14" with #8 @4" The wheel load is 32k x1.6 I will look into Chapter 3 of AASHTO, something we are doing that does not make any sense.
The slabs are spanning between concrete beams that have a span of 59' spaced at 8'-9" do you have any suggestion for beam design with HS20-44. I am using the CALTRANS simple beam span and moment capacity (the beam is connected to retaining walls so really it is not simple) but the moment will be based on wl**2/8 instead of wl**2/12.
Another colleague suggested to get DRbeam pro software. have you heard of that?

Looking forward to your suggestions.

 

[MrHershey]

14" seems about right, but #8 @ 4" seems like a really, really heavily reinforced slab for a 9' span. Is that top and bottom or just at midheight?

 

[casasf]

It is the bottom bars and I still have problems with shear!!

 

[hokie66]

In a continuous slab, more reinforcement is required in the top than in the bottom. Have you taken advantage of continuity? Problems with shear in the slab or in the beams?

 

[casasf]

Sorry. the #8 @ 4" are for negative steel at the supports. Yes we took advantage of continuity. The shear problem is in the slab. we ahve not looked at the beam yet as i am trying to resolve the slab issue.

 

[graybeach]

#8 at 4" for a 14 inch slab sounds like way too much. The wheel load should not be 32 kips. That's for an axle.

 

[bridgebuster]

9" slab should work. I agree completely with graybeach.

 

[casasf]

Thank you Bridgebuster.
Can you get me the exact name of the AASHTO standard specification? Is the title Standard Specifications for Highway Bridges 17th edition-2002? Do they have design examples?

Thanks again.

 

[bridgebuster]

no problem casaf. Standard Specifications for Highway Bridges is the correct title, but, there are no examples. You can download the NYSDOT Bridge Manual. Table 5-2 has predesigned deck slabs.