SOUTH AFRICAN NATIONAL STANDARD

Transcription

1 ISBN SOUTH AFRICAN NATIONAL STANDARD The structural use of masonry Part 2: Structural design and requirements for reinforced and prestressed masonry WARNING To be used in conjunction with SANS Published by Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: fax: international code Standards South Africa

2 Table of changes Change No. Date Scope Amdt Amended to update normative references. Amdt Amended to update referenced standards. Foreword This South African standard was approved by National Committee StanSA SC A, Construction standards Cement, lime and concrete, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This document was published in July This document supersedes SANS :2003 (edition 1.1). A vertical line in the margin shows where the text has been technically modified by amendment No. 2. Annexes A, B, C and D form an integral part of this standard. Annex E is for information only.

3 Contents Foreword 1 Scope Normative references Definitions Symbols Materials and components General New materials and methods Cutting and chasing Selection of mortar and concrete General Concrete infill and grout Admixtures to concrete and grout Chlorides Steel Reinforcing steel Prestressing steel Damp-proof courses Wall ties Bonding of masonry units Design of reinforced masonry General Design considerations Limit states design Limit states Loads and strength of materials Design loads Characteristic compressive strength of masonry f k Characteristic compressive strength of masonry in bending Characteristic shear strength of masonry f v Characteristic tensile strength of reinforcing steel f y Characteristic breaking load of prestressing steel Characteristic anchorage bond strength f b Elastic moduli Analysis of structure General Indeterminate structures Elastic analysis Partial safety factors for materials γ m Construction control Serviceability limit state Ultimate limit state

4 Contents (continued) 7 Detailed design considerations for reinforced masonry General Reinforced masonry subjected to bending General Effective span of elements Limiting dimensions Resistance moments of elements Shear resistance of elements Deflection Cracking Reinforced masonry subjected to a combination of vertical loading and bending General Slenderness ratios of walls and columns Design Deflection Cracking Reinforced masonry subjected to axial compressive loading Reinforced masonry subjected to horizontal forces in the plane of the element Racking shear Bending Detailing reinforced masonry Area of main reinforcement Maximum size of reinforcement Minimum area of secondary reinforcement in walls and slabs Spacing of main and secondary reinforcement Anchorage B minimum area, size and spacing of links Anchorage bond Laps and joints Hooks and bends Curtailment and anchorage Design of prestressed masonry General Design for the ultimate limit state Bending Axial loading Shear Design for the serviceability limit state Design criteria for prestressing tendons Maximum initial prestress Loss of prestress Transmission length in pre-tensioned elements Detailing prestressed masonry Anchorages and end blocks Tendons Links Other design considerations Durability of masonry units and mortars Resistance of metal components to corrosion General Classification and precautions for degrees of exposure

5 Contents (concluded) Exposure situations requiring special attention Effect of different masonry units Cover Prestressing tendons Wall ties Joint finishing Fire resistance Spacing of wall ties Drainage and waterproofing Damp-proof courses Work on site Materials Construction General Grouted-cavity construction Reinforced hollow masonry unit walls Quetta bond and similar walls Pocket-type walls Prestressing operations Forming chases and holes, and providing fixings Jointing and pointing Quality control Workmanship Materials Annex A (normative) Wall tie for high-lift cavity wall Annex B (normative) Design methods for walls incorporating bed joint reinforcement to enhance lateral load resistance Annex C (normative) Estimation of deflection Annex D (normative) Test method of determination of characteristic compressive strength of masonry units f k Annex E (informative) Bibliography