Expansion Joint in Slab-on-Grade
Expansion Joint in Slab-on-Grade
(OP)
Hi,
Can a key and groove joint in a slab be treated as expansion joint such that the bars (both top and bottom) extending into second pour are terminated in second pour and greased viz. they can slide during expansion and contraction.
Do we have a code recommendation for such a system.
Thanks
Can a key and groove joint in a slab be treated as expansion joint such that the bars (both top and bottom) extending into second pour are terminated in second pour and greased viz. they can slide during expansion and contraction.
Do we have a code recommendation for such a system.
Thanks






RE: Expansion Joint in Slab-on-Grade
Why don't you actually place the expansion joint? then to cover it with the special expansion joints capping?
In general, as I know, building may extend up to 60 meters without an expansion joint.
RE: Expansion Joint in Slab-on-Grade
For dowels to work, they must be smooth, I'm not sure if you were planning on using non-deformed bars.
Dik
RE: Expansion Joint in Slab-on-Grade
RE: Expansion Joint in Slab-on-Grade
informative link
http://www.everything-about-concrete.com/concrete-...
RE: Expansion Joint in Slab-on-Grade
Dik
RE: Expansion Joint in Slab-on-Grade
RE: Expansion Joint in Slab-on-Grade
Dik
RE: Expansion Joint in Slab-on-Grade
For an external slab which can really feel the temperature I would recommend expansion joints but not by having deformed bar crossing the joint. I would use a smooth dowel and a sleeve.
RE: Expansion Joint in Slab-on-Grade
RE: Expansion Joint in Slab-on-Grade
More important to control slab thickness and make sawcuts at proper time than to provide for "expansion".
RE: Expansion Joint in Slab-on-Grade
Dik
SLAB ON GRADE
THE MODULUS OF SUB-GRADE REACTION IS ASSUMED TO BE 200 PCI. THE CONTRACTOR, THROUGH THE CLIENT IS RESPONSIBLE FOR OBTAINING A GEOTECHNICAL REPORT TO CONFIRM THIS DESIGN ASSUMPTIONS. THE [CONSULTANT | ENGINEER] ASSUMES NO LIABILITY FOR THESE DESIGN ASSUMPTIONS OR FOR ANY FOUNDATION REDESIGN NECESSITATED BY DIFFERING SOIL CONDITIONS
TEMPERATURE DIFFERENTIAL BETWEEN THE GRANULAR BASE AND THE TOP OF THE CONCRETE SLAB SHALL BE MINIMISED
SLAB FINISHING SHALL BE DELAYED AS LONG AS POSSIBLE
THE IS DESIGNED FOR [LIGHT | MEDIUM | HEAVY] DUTY USE ONLY
THE EXPOSED SUB-GRADE FOR SLAB ON GRADE SHALL BE PROOF ROLLED. SOFT SPOTS SHALL BE EXCAVATED, BACK-FILLED WITH GRANULAR FILL AND COMPACTED TO 95% [SPDD | MPDD]. GRANULAR FILL AND COMPACTION METHODS TO BE APPROVED BY THE [CONSULTANT | ENGINEER]
PROVIDE MIN [6 IN | 150 MM] CMPT GRAN 'A' BASE COURSE BENEATH SLAB-ON-GRADE U/N. CMPT TO 95% [SPDD | MPDD] U/N
PROVIDE MIN [6 IN | 150 NN] CMPT GRAN 'B' SUB-BASE COURSE BENEATH BASE COURSE U/N. CMPT TO 100% [SPDD | MPDD] U/N
THE COMPACTED GRANULAR FILL SHALL PROVIDE A UNIFORM SURFACE WITH NO ABRUPT CHANGES IN LEVEL. MAX DEVIATION IN LEVEL SHALL NOT EXCEED [0.5 IN | 12 MM]
INSTALL [6 MIL | 0.15 MM] PEVB MEMBRANE CONFORMING TO CAN3-51.33-M80 BTN SLAB AND FILL WITHIN THE AREA OF THE BUILDING
LAP PEVB JOINTS [12 IN | 300 MM] MIN AND SEAL WITH MASTIC CEMENT
U/N REINF FOR SLAB-ON-GRADE SHALL BE (0.2%):
DEPTH REINF
5 10M@16 TEW
6 10M@13 TEW
6 15M@24 TEW
7 15M@22 TEW
8 15M@19 TEW
8 10M@20 T&BEW
U/N REINF FOR SLAB-ON-GRADE SHALL BE (0.25%):
DEPTH REINF
5 10M@12 TEW
6 15M@20 TEW
7 15M@17 TEW
8 15M@15 TEW
8 10M@16 T&BEW
U/N REINF FOR SLAB-ON-GRADE SHALL BE (0.3%):
DEPTH REINF
5 15M@20 TEW
6 15M@16 TEW
7 15M@14 TEW
8 15M@12 TEW
8 15M@24 T&BEW
U/N REINF FOR SLAB-ON-GRADE SHALL BE:
DEPTH REINF
125 10M@400 TEW
150 10M@330 TEW
175 15M@550 TEW
200 15M@510 TEW
200 10M@510 T&BEW
LAP WELDED WIRE FABRIC, ONE FULL MESH AT SPLICES
REINF STEEL TO BE LOCATED [2 IN | 50 MM] BELOW TOP OF FINISHED FLR SLAB U/N
SUPPORT SLAB TOP REINF ON HIGH CHAIRS AND/OR 15M SUPPORT BARS WHERE REQUIRED. ALL BARS AND CHAIRS MUST BE SECURELY TIED TOGETHER
PROVIDE SUFFICIENT CHAIRS AND SUPPORT BARS TO MAINTAIN CONC PROTECTION AS SPECIFIED
CUTTING OF CONTROL JOINTS SHALL BEGIN AS SOON AS THE CONC SURFACE HAS HARDENED SUFFICIENTLY TO RESIST RAVELLING AS THE CUT IS MADE. SAWCUTTING SHOULD COMMENCE APPROX 6 TO 8 HOURS AFTER FINISHING SLAB
SAWCUT SLABS INTO PANELS NOT EXCEEDING 20' IN ANY DIRECTION. MAX CONTROL JOINT SPACING SHALL PREFERABLY NOT EXCEED 30 TIMES THE SLAB THICKNESS AND SHALL NOT EXCEED 36 TIMES THE SLAB THICKNESS. THE LENGTH TO WIDTH RATIO OF THE CONTROL JOINT PANELS SHALL NOT EXCEED 1.5. IF A SAWCUT INTERSECTS ANOTHER SAWCUT, THE SMALLER ANGLE OF INTERSECTION SHALL NOT BE LESS THAN 50 DEGREES
CONTRACTOR SHALL PROVIDE SHOPDRAWING SHOWING THE PROPOSED CUTTING PATTERN AND THE PROPOSED SAWCUTTING PROCEDURE WELL IN ADVANCE OF PLACING THE CONCRTE FOR THE SLAB ON GRADE
CONC SLAB-ON-GRADE HAS BEEN DESIGNED FOR THE FOLLOWING:
WHEEL LOAD XXXX POUNDS
INFLATION PRESSURE XXX PSI
DIM A XXX
DIM B XXX
DIM C XXX
LOAD REPETITIONS XXXXX THOUSAND
SAFETY FACTOR XXX
IF DIM A=0 THEN VEHICLE AXLE HAS SINGLE WHEELS
IF DIM B=0 THEN VEHICLE HAS SINGLE AXLE ONLY
SLAB FLATNESS
SLAB FLATNESS SHALL BE [ 20/15 | 25/20 | 35/25 | 45/35 | 65/40 | 100/50 | FM1 | FM2 | FM3 ]
U/N FLOORS SHALL HAVE A DEGREE OF FLATNESS DEFINED BY THE FACE FF/FL NUMBER THAT SHALL NOT BE LESS THAN:
20/15 MECHANICAL ROOMS, PARKING STRUCTURES, ETC.
25/20 CARPETED AREAS OF COMMERCIAL OFFICE BUILDINGS
35/25 TYPICAL WAREHOUSE FOR MODERATE/HEAVY RANDOM TRAFFIC, FACTORY, ETC.
45/35 CONSIDERED 'FLAT' TYPICAL WAREHOUSE WITH AIR PALLET USE, ICE RINKS, ETC.
65/40 CONSIDERED 'VERY FLAT'
100/50 CONSIDERED 'SUPER FLAT'
ALTERNATIVELY,
THE MAX VERTICAL DEVIATION OVER A [24 | 600] WIDTH SHALL NOT EXCEED
2.5mm (quality FM1)
3.5mm (quality FM2)
5.0mm (quality FM3)
THE MAXIMUM VERTICAL DEVIATION OVER A [10FT | 3.0M] WIDTH SHALL NOT EXCEED
3.0mm (quality FM1)
6.0mm (quality FM2)
8.0mm (quality FM3)
FLATNESS TESTING MAY COMMENCE 16 HOURS AFTER SLAB FINISHING. FLATNESS TESTING SHALL BE COMPLETED WITHIN 72 HOURS OF SLAB FINISHING
RE: Expansion Joint in Slab-on-Grade
So my exterior slab is 34" thick. It s 300 ft x 180 ft approx. I have divided the slab into sections seperated by tongue and groove contraction joints. To allow for the potential expansion, I have greased the bars protuding from first into second pour at construction joints typically 70 ft - 115 ft O.C.
ACI 224 recommends that shrinkage / contraction is more of an issue than expansion. ACI does not refer to any sort of calulation for expansion within slab on grade. So to account for the worst of both worlds, In the absence of much guidance from ACI on the matter, I am leaned towards recommending a joint such as described above. I am concerned that if I provide expansion joint with filler, there may be a vertical movement between the slab....Opinion about the solution much appreicated.
Thanks
RE: Expansion Joint in Slab-on-Grade
BA
RE: Expansion Joint in Slab-on-Grade
RE: Expansion Joint in Slab-on-Grade