CITY OF LOS ANGELES CALIFORNIA

Transcription

1 BOARD OF BUILDING AND SAFETY COMMISSIONERS MARSHA L. BROWN PRESIDENT VAN AMBATIELOS VICE-PRESIDENT VICTOR H. CUEVAS HELENA JUBANY ELENORE A. WILLIAMS CITY OF LOS ANGELES CALIFORNIA ANTONIO R. VILLARAIGOSA MAYOR DEPARTMENT OF BUILDING AND SAFETY 201 NORTH FIGUEROA STREET LOS ANGELES, CA ANDREW A. ADELMAN, P.E. GENERAL MANAGER RAYMOND CHAN EXECUTIVE OFFICER ARXX Corporation RESEARCH REPORT: SW 72 nd Ave, Ste 100 (CSI #03135) Portland, OR Expires: November 1, 2010 Attn: Rita Hansen, Director Issued: November 1, 2008 (971) Ext 110 Code: 2008 LABC GENERAL APPROVAL Revision - DETAILS General: The consists of individual blocks that form a permanent formwork system for reinforced concrete beams, lintels, walls, foundation walls and retaining walls. Walls constructed as described in this report are permitted to be used as loadbearing and non-load bearing walls resisting axial, racking and transverse loads in Type II, III and Type V construction in accordance with 2008 LABC. The APEX Block TM Interlocking System is also classified as 3-hour fire-resistance rated, limited load-bearing wall when constructed in accordance with this report. See Figures 1, 2 and 3 for details of the system. Materials: The consists of APEX blocks, concrete and reinforcement. APEX Blocks: APEX blocks are manufactured from a mixture of recycled expanded polystyrene (EPS) aggregate, Type I or II Portland cement, a proprietary accelerant solution and water. A standard block is 10 inches high, 16 inches high and 48 inches long. Each block is molded with 6 inch vertical and horizontal cores. When stacked, the blocks form vertical and horizontal cavities where concrete and reinforcement are placed. Concrete: Block cores shall be filled at the jobsite with normal-weight concrete having carbonate or siliceous aggregate with a 3/8 inch maximum aggregate size and an 8-inch slump. The concrete shall have 3000 psi minimum compressive strength. Reinforcement: ASTM A 615 Grade 60 deformed steel reinforcing bars shall have minimum yield strength of 60 ksi. Page 1 of 8 LADBS G-5 (Rev.6/08) AN EQUAL EMPLOYMENT OPPORTUNITY - AFFIRMATIVE ACTION EMPLOYER

2 Design: The design of cast-in-place, reinforced concrete structural members formed by APEX Block TM Interlocking System blocks must conform to Chapters 16 and 19 of the 2008 LABC with the following requirements: 1. Minimum vertical and horizontal reinforcement shall be No. 4 for all Seismic Design Categories (2008 LABC) spaced a maximum of 16 inches on center. The reinforced bar sizes may need to be increased, depending upon demand loads, as a result of the structure being designed under Chapters 16 and 19 of 2008 LABC. 2. Development and splices of reinforcement shall be in accordance with Chapter 12 of ACI Calculations shall be based on the assumption that the APEX Block TM Interlocking System Wall behaves as a solid-concrete wall having an equivalent thickness, b eq, equal to 4.5 inches for walls with 6-inch-diameter horizontal and vertical cores. 4. The strength reduction factor, φ, with a value of 0.85 shall be used. 5. A shape reduction factor,ψ, with a value of 0.85 shall be used. 6. For members subject to shear and flexure only, the nominal shear strength provided by the concrete is determined as follows: V c = 2 φ ψ sqrt(f c ) b eq d where: b eq = Width of an equivalent rectangular section equal to 4.5 inches for 6 inch cores d = Distance from extreme compression fiber to centroid of tension reinforcement (inches) f c = Specified compressive strength of concrete (psi) φ = Strength reduction factor equal to 0.85 ψ = Shape-reduction factor equal to In-plane shear strength of shear walls is determined as follows: F v = φ ψ sqrt(f c )L u b eq where: b eq = Width of an equivalent rectangular section equal to 4.5 inches for 6 inch cores L u = Total length of shear wall panel (inches) f c = Specified compressive strength of concrete (psi) φ = Strength reduction factor equal to 0.85 ψ = Shape-reduction factor equal to 0.85 Page 2 of 8

3 8. The length of the wall considered the effective length for concentrated vertical loads shall be based on the design of a concrete bond beam at the top of the wall engineered to distribute vertical loads to vertical concrete cores. 9. Wall subject to axial loading or combined flexural and axial loading shall be designed as compression members in accordance with requirements of ACI Anchorage to foundations shall comply with requirements of ACI The used as a foundation stem wall shall be designed in accordance with Section of 2008 LABC. 12. The used as a retaining wall shall be designed in accordance with this report and accepted engineering principles. The approval is subject to the following conditions: 1. Complete design and calculation shall be prepared by an engineer licensed in the State of California and approved by the structural plan check. 2. The maximum allowable pour rate of the forms shall be 4 feet per hour. 3. Continous inspection by Deputy Inspectors shall be provided for placement of reinforcing steel and concrete. Any exception shall be approved by structural plan check supervisors. 4. The Wall Forms units are limited to use in buildings that are combustible construction. 5. The Wall system shall be supported on concrete footings complying with Chapter 18 of 2008 LABC. Vertical rebar, embedded in the footing, shall extend into panel wall system a minimum of 24 inches, or a length complying with requirements of ACI , whichever is greater. 6. The blocks may be laid horizontally or vertically provided horizontal and vertical reinforcement is placed in accordance with approved building plans. 7. Horizontal reinforcement is permitted to rest directly on blocks. 8. Concrete must fill all voids of the wall blocks. Concrete can be placed in lifts in compliance with manufacturer s installation instructions. Field verification of a proper pour can be accomplished by pushing a 1/4 inch diameter steel rod through the face shell of the blocks into concrete core and noting upon its withdrawal the presence of wet concrete on the rod. Page 3 of 8

4 9. Wood ledgers shall be attached to the wall. The face shell of the panel may remain in place. Wood ledgers are attached by cutting 6-inch diameter holes into the face shell of the panel before placement of concrete at the location of a horizontal or vertical core at spacing required by design. A dam shall be used to hold the J-bolt centered in the hole. When concrete is poured into the wall system, the holes provided for the J-bolts form a solid concrete connection from the ledger board to the horizontal bond beam. 10. Wood plates must be anchored to the top of the wall. Anchor bolts used to connect the wood ledgers or the plates to the concrete shall be cast-in-place, with the bolts sized and spaced as required design. 11. wall blocks are permitted to be exposed to the interior where allowed by the code. The flame spread index is 25 or less and smoke developed index is 50 or less. 12. Exterior walls shall be covered with approved wall covering in accordance with requirements of Chapter 14 of 2008 LABC. 13. For below grade applications, wall surfaces shall be damp-proofed and water proofed in accordance with requirements of Section 1807 of 2008 LABC. 14. Wood members in contact with concrete for plates of window and door framing shall be treated with an approved wood preservative in accordance with the applicable code. 15. Structures in all seismic zones are limited to two stories with basement and maximum 10- foot unsupported wall heights. Any exception shall be approved by structural plan check supervisors. 16. The is limited to use as a structural concrete wall lateral-force resisting system in Seismic Design Categories A and B under the 2008 LABC. Page 4 of 8

5 (a) (b) Figure 1 (a) APEX Block TM Plan View (b) Isometric View Page 5 of 8

6 Figure 2 Lintel and APEX Block TM Layout Page 6 of 8

7 Figure 3 Reinforcement Placement Page 7 of 8

8 DISCUSSION The revision is to add the condition that the APEX Block Interlocking System is limited to use as a structural concrete wall lateral-force resisting system in Seismic Design Categories A and B under the 2008 LABC. The report is in compliance with 2008 Los Angeles Building Code. The approval is based on tests in accordance with ICC ES Acceptance Criteria (AC 15). This general approval will remain effective provided the Evaluation Report is maintained valid and unrevised with the issuing organization. Any revision to the report must be submitted to this Department for review with appropriate fee to continue the approval of the revised report. Addressee to whom this Research Report is issued is responsible for providing copies of it, complete with any attachments indicated, to architects, engineers and builders using items approved herein in design or construction which must be approved by Department of Building and Safety Engineers and Inspectors. This general approval of an equivalent alternate to the Code is only valid where an engineer and/or inspector of this Department has determined that all conditions of this Approval have been met in the project in which it is to be used. YEUAN CHOU, Chief Engineering Research Section 201 N. Figueroa St., Room 880 Los Angeles, CA Phone Fax TV:tvo RR/MSWord2003 R12/01/09 2C/ACI Page 8 of 8