WRI Continuing Education Program

WIRES USED IN WELDED WIRE REINFORCEMENT ARE PRODUCED FROM HOT-ROLLED ROD AND UNDERGO A COLD-WORKING PROCESS TO ARRIVE AT A FINAL DESIGN DIAMETER.

PER ASTM A1064, WELDING OF WWR MATS RELIES ON THE PROPER AMOUNT OF PRE-HEAT AND SELECTION OF THE CORRECT CONSUMABLE ELECTRODE TYPE TO ACHIEVE THE INTENDED WELD COMPOSITION AND GEOMETRY.

THE FOLLOWING CONSIDERATIONS MUST BE MADE IN THE ENGINEER OF RECORD’S STRUCTURAL DESIGN OF TILT-UP WALL PANELS:

1. SLENDERNESS EFFECTS
2. OUT-OF-PLANE WIND LOADING
3. INTERIOR STEEL COLUMN CONNECTION TO JOIST GIRDER
4. ALL OF THE ABOVE
5. A&B ONLY

THE FOLLOWING ATTRIBUTE HAS THE MOST SIGNIFICANT IMPACT ON THE CALCULATION OF THE WALL’S STIFFNESS:

1. LIMITING AGGREGATE SIZE TO 3/4
2. THE STEEL REINFORCEMENT YIELD STRENGTH, fy
3. THE STEEL REINFORCEMENT CROSS-SECTIONAL AREA,As
4. THE TRIBUTARY AREA OF ROOF LOADING CARRIED BY THE WALL
5. THE CONNECTION OF THE WALL PANEL TO THE FOUNDATION

THE WELD PROCESS USED IN THE MANUFACTURE OF WWR IS CALLED:

1. SHIELDED METAL ARC WELDING
2. INERT GASE DISPLACEMENT METHOD
3. GAS METAL ARC WELDING
4. GAS TUNGSTEN ARC WELDING
5. ELECTRICAL RESISTANCE WELDING

WHICH ATTRIBUTE OF A WWR MAT IS NOT VARIABLE:

1. WIRE SIZE
2. WIRE SPACING
3. WIRE LENGTH
4. WELD ANGLE OF WIRE INTERSECTION
5. WIRE YIELD STRENGTH

THE CRACKED SECTION MOMENT OF INERTIA IS CRITICAL TO ESTABLISHING THE FOLLOWING CHARACTERISTIC OF THE WALL PANEL:

1. AXIAL STRENGTH
2. OUT-OF-PLANE STIFFNESS
3. BREAKOUT CAPACITY AT EMBEDDED PLATE ANCHORS
4. RESISTANCE TO IN-PLANE OVERTURNING
5. THE REQUIRED YIELD STRENGTH OF THE STEEL REINFORCEMENT

AN INCREASE IN THE CRACKED SECTION MOMENT OF INERTIA CAN BE ACHIEVED BY:

1. INCREASING THE CROSS-SECTIONAL AREA OF REINFORCING STEEL
2. INCREASING THE EFFECTIVE DEPTH, d, MEASURED FROM COMPRESSION FACE OF WALL PANEL TO CENTER OF REINFORCEMENT
3. INCREASING THE EFFECTIVE DEPTH, d, MEASURED FROM COMPRESSION FACE OF WALL PANEL TO CENTER OF REINFORCEMENT
4. A, B, AND C
5. A AND B

THE STRENGTH CALCULATION OF THE MOMENT AT THE MID-HEIGHT OF THE WALL PANEL, Mua, IS A FUNCTION OF THE FOLLOWING:

1. IN-PLANE MOMENT DUE TO WIND FORCE PLUS THE AXIAL LOADING ABOVE ALL WALL OPENINGS
2. OUT-OF-PLANE TEMPERATURE EFFECTS MINUS THE EFFECTS OF AXIAL LOADING DUE TO FLOOR FRAMING
3. IN-PLANE TEMPERATURE EFFECTS PLUS THE EFFECTS OF AXIAL LOADING DUE TO FLOOR FRAMING
4. OUT-OF-PLANE MOMENT DUE TO WIND OR SEISMIC FORCES PLUS ECCENTRIC AXIAL EFFECTS OF ROOF AND/OR FLOOR LOADING
5. IN-PLANE MOMENT DUE TO WIND OR SEISMIC FORCES PLUS ECCENTRIC AXIAL EFFECTS OF ROOF AND/OR FLOOR LOADING

THE VERTICAL STEEL REINFORCEMENT AREA IS ALSO KNOWN AS THE EFFECTIVE AREA OF LONGITUDINAL REINFORCEMENT.

IN CARRYING OUT A STRENGTH CHECK OF THE WALL, THE FOLLOWING STEP IS MOST CRITICAL:

1. USING EFFECTIVE MOMENT OF INERTIA, Ieff, IN THE DETERMINATION OF FACTORED MOMENT INCLUDING P-DELTA EFFECT
2. CALCULATING THE DESIGN MOMENT STRENGTH, ϕM, USING THE CROSS-SECTIONAL AREA OF STEEL, A,_S.
3. CALCULATING THE CRACKED MOMENT OF INERTIA USING BISCHOFF'S EQUATION
4. CHECKING ALL RELEVANT CODE-PRESCRIBED LOAD COMBINATIONS
5. CHECKING CODE-PRESCRIBED LOAD WITH OUT-OF-PLANE LOADS ONLY

A LOAD FACTOR OF 1.0 MUST BE APPLIED TO WIND OR SEISMIC FORCES WHEN CARRYING OUT A SERVICE DEFLECTION CHECK OF THE TILT-UP WALL PANEL.

IN THE ABSENCE OF ADDITIONAL ANALYSIS, IT IS ACCEPTABLE TO DIRECTLY SUBSTITUTE THE FOLLOWING AS A REPLACEMENT FOR AN ORIGINALLY-DESIGNED 2.0 in² OF 60 KSI REINFORCEMENT:

1. 2.0 IN² OF 80 KSI REINFORCEMENT
2. 1.5 IN² OF 80 KSI REINFORCEMENT
3. 2.5 IN² OF 60 KSI REINFORCEMENT
4. ALL OF THE ABOVE
5. NONE OF THE ABOVE

A SET OF STRUCTURAL CONTRACT DOCUMENTS SHOULD CONTAIN THE FOLLOWING WWR INFORMATION IN ORDER FOR THE WWR DETAILER TO PREPARE THE REINFORCEMENT SUBMITTAL:

1. WWR MAT MAXIMUM WIDTHS AND LENGTHS
2. REINFORCEMENT SIZE AND SPACING REQUIREMENTS
3. REINFORCEMENT STEEL AREA AND MAXIMUM SPACING REQUIREMENTS
4. B AND D ONLY
5. A, B, AND C

WELDED WIRE REINFORCMENT SUBMITTALS FOR TILT-UP WALL PANEL PROJECTS CONTAIN FULLY-DIMENSIONED WWR MAT DIAGRAMS AND PANEL PLACEMENT ELEVATIONS.

IF A CONTRACTOR PROPOSES AN ALTERNATIVE TO THE ORIGINAL STRUCTURAL DESIGN THAT IS COMPRISED OF A SMALLER CROSS-SECTIONAL AREA OF HIGHER YIELD STRENGTH REINFORCEMENT, THE FOLLOWING MUST OCCUR:

1. THE ENGINEER’S SHOP DRAWING STAMP MUST BE MARKED “DESIGN BY CONTRACTOR”
2. THE SHOP DRAWINGS MUST CONTAIN THE WWR DETAILER’S CONVERSION CALCULATIONS
3. THE ENGINEER MUST VERIFY THAT THE SUBSTITUTION STILL SATISFIES THE ORIGINAL DESIGN INTENT
4. A AND C
5. B AND C

BENEFITS OF USING WWR IN TILT-UP WALL PANEL PROJECTS CAN INCLUDE:

1. TIGHT TOLERANCE CONTROL ON REINFORCEMENT POSITIONING WITHIN THE PANEL
2. QUICKER INSTALLATION TIME
3. INTUITIVE WWR SHOP DRAWING REVIEW PROCESS
4. ALL OF THE ABOVE
5. B ONLY

THE TWO CATEGORIES OF WWR MAT TYPES USED IN TILT-UP WALL PANELS ARE:

1. UNI-DIRECTIONAL AND BI-DIRECTIONAL
2. MULTI-SPAN AND ORTHGONAL-SPAN
3. DISTRIBUTED AND BANDED
4. INNER AND OUTER
5. LONGITUDINAL AND TRANSVERSE

WWR MATS ARE IDENTIFIED ON SITE BY THE FOLLOWING:

1. MARKS STAMPED INTO THE STEEL WIRES OF EVERY TENTH MAT IN A BUNDLE
2. MARKS STAMPED INTO THE STEEL WIRES OF EVERY MAT IN A BUNDLE
3. PRINTED TAGS ON EACH MAT BUNDLE
4. COLOR-CODED STRAPPING ON EACH MAT BUNDLE
5. COLOR-CODED PAINT ON EACH MAT BUNDLE

MULTI-STORY WALL PANELS ARE TYPICALLY MORE SUCEPTIBLE TO SLENDERNESS EFFECTS THAN SINGLE-STORY WALL PANELS.