SB 66/ use of WOOD FORMS for support of concrete

Question 1

Method of forming poured concrete floors

Answer 1

• 5/8” or 3/4” plywood hold in place by 4”x4” wood studs

- one shoring stud placed every 4 FEET on center extending from floor to underside of plywood form above

Question 2

Heavy fire load.

Answer 2

storage of sheets of plywood and wood studs previously stripped from a CURED FLOOR
-lumber usually found stored on floor which is 2 LEVELS below the most RECENTLY POURED FLOOR and will serve as the forms for the next floor to be poured

-problems on this floor are not structural failure but HEAVY FIRE LOAD

Question 3

Determine how STRUCTURALLY SOUND the most recently poured floor is …

Answer 3

must be known WHEN CONCRETE was poured , how many HOURS CONCRETE HAS BEEN CURING
-obtaining this info difficult and not always accurate, unless there is a responsible person on the job site, CONSTRUCTION ENGINEER , BUILDING SUPERINTENDENT OR CONCRETE FOREPERSON AND THEY CAN STATE EXACTLY TIME IT WAS POURED, IF THEY CAN’T

ASSUME CONCRETE WAS POURED IN PRIOR 24 HOURS

Question 4

STRUCTURAL STABILITY of the actual floor BELOW the recently poured floor should be considered SOUND

Answer 4

It is required that every floor that has been stripped of its supporting plywood forms and is inits curing stage be RESHORED
-this restoring of 4”x4” stud placed every 8 FEET will usually be found at least 8 Floors below the most recently poured floor

• if units observe studs placed approximately 8 FEET APART , as they proceed upward in the building, RESHORING IS INDICATED…IT SHOULD BE ASSUMED THESE FLOORS ARE IN ADVANCED CURING SATE AND SHOULD NOT PRESENT A PROBLEM IF EXPOSED DURING FIRE CONDITIONS
• KEY TO SAFE OPERATION IS KNOWLEDGE OF CURING TIME