SAMCHAI STEEL INDUSTRIES

Thai l Eng

Building Code Requirements

Spacing of Wires
Inwalls and slabs other than concrete joist construction, the principal reinforcement shall not be spaced farther apart than 3 thimes the wall or slab thickness, nor more than 18 inches (457 mm)....................................................................

ACI-318-89 Section 7.6.5

In slabs where principle reinforcement extends in one direction only, shrinkage and temperature reinforcement at right angles to the principle reinforcement shall be spaced not farther apart than 5 times the salb thickness, nor more than 18 inches (457 mm)...............................................

ACI 318-89 Section 7.12.8

Minimum Reinforcement Requirements
For shrinkage and temperature reinforcement in structurally reinforced slabs* :

1.	Slabs where welded wire fabric with fy = 65,000 psi (448 MPa) ; (ACI 318 assigns fy = 60,000 psi (414 MPa) but makes provision for the use of higherfy provided the stress corresponds to a strain of 0.35%). Use ratio of reinforcement-to-gross concrete area of 0.0018.............................................................
2.	Slabs where welded wire fabric exceeds 65,000 psi (448 MPa), use 0.0018 x 60,000 when fy exceeds 60,000 psi (414 MPa), material shall be measured at a yield strain of 0.35%, but not less than 0.0014...

ACI 318-89 Section 7.12.2.1 (b) ; (c)

For minimum wall reinforcement:

Wall designs require the following minimum reinforcement ratios when reinforced with welded wire fabric (wire sizes not larger than W31 or D31)
(MW200 or MD200)..............................................
Vertical -0.0012...................................................
Horizontal -0.0020................................................

ACI 31889 Section 14.3.2;3

Splices The splice length in inches shall be the largest of the values shown in the figures below.

(a)

but not less than 1 space + 2"(51 mm) nor 6" (152 mm) minimum Note : overhangs must be added to the splice length for plain fabric.

(b)

Plain Wire Fabric Splice Lengths

Design Methods and Details.

Designs shall not be based on yield strength (fy) in excess of 80,000 psi (552 MPa), except for prestressing tendons.......

ACI 318.89 Section 9.4

Welded wire fabric ASTM yield Strengths are specifield at 0.50 percent strain. ACI specifiles use of maximum design yield strengths of 60,000 psi (414 MPa) unless fy is measured at 0.35 percent strain.....................................................

ACI 318-89 Section 3.5.3.4;5.3.5.4.2

SUBSTITUTION OF

S.C. WIRE MESH FOR MILD STEEL BARS

R.C. PAVEMENT ....AASHTO M-32
Reinforcement for concrete reinforcements is designed to hold cracks that result from flexural stress*v tightly cloded. The assumption is that the reinforcing steel must be strong enough to drag both ends of individual slab over the subgrade toward its center. The idea expressed as aformular becomes;

Specifications and Properties

ตารางที่ 1 ขนาดและเกณฑ์ความคลาดเคลื่อนของลวด SIDE A PERMISSIBLE VARIATION (ข้อ 3.1)

มอก. 737-2531

สัญลักษณ์ของลวดยืนและลวดขวาง	เส้นผ่านศูนย์กลาง/มิลลิเมตร	เกณฑ์ความคลาดเคลื่อนของเส้นผ่านศูนย์กลาง/มิลลิเมตร	พื้นที่หน้าตัด ระบุ ตาราง มิลลิเมตร
CDR2	2.0		3.14
CDR2.3	2.3		4.16
CDR2.6	2.6		5.31
CDR3	3.0		7.07
CDR3.3	3.3		8.56
CDR3.6	3.6		10.18
CDR4	4.0		12.57
CDR4.3	4.3		14.53
CDR4.6	4.6	+/- 0.1	16.63
CDR5	5.0		19.64
CDR5.3	5.3		22.07
CDR5.6	5.6		24.64
CDR6	6.0		28.29
CDR6.5	6.5		33.20
CDR7	7.0		38.50
CDR7.5	7.5		44.20
CDR8	8.0		50.29
SIZE NUMBER	DIAMETER(MM.)	PERMISSIBLE VARIATION	SECTION (mm2)

TABLE 3 Minimum Requirements of steel Wires in Welded Wire Fabric

WELDED PLAIN WIRE FABRIC ASTM A185, CSA G30.5

Wire Size

Tensile Strength psi

Yield Strength psi

Weld Shear Strength

W1.2% & over

75,000
(517 MPa)

65,000
(448 MPa)

35,000
(241 MPa)

under
W1.2

70,000
(483 MPa)

56,000
(386 MPa)

WELDED DEFORMED WIRE FABRIC ASTM A497, CSA G30.15

Wire Size

Tensile Strength psi

Yield Strength psi

Weld Shear Strength

D31
thru D4

80,000
(552 MPa)

70,000
(483 MPa)

35,000
(241 MPa)

under
D4

80,000
(552 MPa)

70,000
(483 MPa)

S.C.STANDARD SQUARE MESH

WIRE	SECTION AREA	SECTION AREA AT DIFFEREUT SPACINGS (mm2/m)
(mm)	(mm2)	15	20	25	30
4.0	12.6	84	63	50	-
5.0	19.6	131	98	78	65
6.0	28.3	189	142	113	94
6.5	33.2	221	166	133	94
7.0	38.5	257	193	154	128
7.5	44.2	295	221	177	147
8.0	50.3	335	252	201	168
8.5	56.7	378	284	227	189
9.0	63.6	424	318	254	212
10.0	78.5	523	393	314	262
11.0	95.0	633	475	380	317
12.0	113.1	754	566	452	377

S.C.STANDARD RECTANGULAR MESH

WIRE (mm)	10 x 20		10 x 30		15 x 20
	Section Area (mm2/m)		Section Area (mm2/m)		Section Area (mm2/m)
	Long	Cross	Long	Cross	Long	Cross
4.0	126	63	126	42	84	63
5.0	196	98	196	65	131	98
6.0	283	142	283	94	189	142
6.5	332	166	332	111	221	166
7.0	385	196	385	128	257	193
7.5	442	221	442	147	295	221
8.0	503	252	503	168	335	252
8.5	567	284	567	189	378	284
9.0	636	318	636	212	424	318
10.0	785	393	785	262	523	393
11.0	950	475	950	317	633	475
12.0	1131	566	1131	377	754	566