1980 spancrete load tables 2

[structSU10]

Does anyone have span tables for 1980's spancrete? I have a building that has 8504T to 8510T planks specified.

 

[Ingenuity]

Spancrete made/make HC planks with 40", 48", and 96" wide panels, depending on the precaster and their equipment.

Here is a load table for a 48" plank width, with 1" strand cover, 250 k strand, for both topped and untopped panels:

Full 8" load tables available here for varying bottom strand covers: Link

I am not completely certain what the "8xxxT" designation means, except the "8" is the plank depth, and the "T" is for topped. The other three numerals probably refer to strand # and dia, for example: "8608T" - would be 8" deep Topped plank, with 6 each x 08/16" (i.e 1/2") dia strand.

If structurally warranted, you may have to do some field verification: subsurface radar, probing, visual, dimensional etc.

To check/verify what the designation refers, you could back calc the nominal flexural capacity, M[sub]n[/sub], based upon say (randomly selected) "8706" plank (8" deep, 7 each strands of [sup]3[/sup]/[sub]8[/sub]" dia @ 250 ksi) and see if it gives you 18.98 ft-k/ft, as per attached:

 

[structSU10]

Thanks for the info Ingenuity. I was mainly hoping to see the 'vintage' tables, as I noticed the 8504T noted on plans are not in the newer tables. Also, did they tend to use 250 ksi steel in the 80's?

 

[robyengIT]

not sure if spancrete and flexicore are similar or the same production group (I am Italian) but few months ago someone posted the attached tables (from 1954 to 1978 if I am not wrong). I hope it can help

 

[JLNJ]

My PCI first edition Handbook shows calcs for 270 ksi strands back in the 80s and much earlier.


Spancrete and Flexicore are quite a bit different, so you need to be careful using Flexicore tables.

 

[briancpotter]

Spancrete series are named as follows: First digit is plank thickness, second is strand diameter (in 16ths of an inch), third and fourth are number of strand, T indicates structural topping. So 8504T would be 8" thick plank with (4) 5/16" strand, and 8510T would have (10) 5/16" strand

The number and letter before the series indicate strand height and core shape. 1.0F indicates 1" clearance with the "F" core series.

If you contact someone at Spancrete they can probably dig up a load table from the 80's for you.

Brian C Potter, PE
Simple Supports - Back at it again with the engineering blog.

 

[Ingenuity]

Spancrete series are named as follows: First digit is plank thickness, second is strand diameter (in 16ths of an inch), third and fourth are number of strand, T indicates structural topping. So 8504T would be 8" thick plank with (4) 5/16" strand, and 8510T would have (10) 5/16" strand

Good to know. Thanks for that. I figured I had it backwards when my way would have had a "8712T" designation using 12/16" dia strand - 0.75" - which is not available, as far as I have experienced.

Also, did they tend to use 250 ksi steel in the 80's?

For pretensioned members generally (not necessarily Spancrete products) I have seen both 250 and 270 ksi, and for older strand system, they were stress-relieved strand, and low-relaxation for newer projects (maybe mid-80's onward??).

We have removed 60" lengths of strand from planks and undertaken mechanical testing - ultimate tensile and elongation - when justified.