TABLE OF CONTENTS DECLARATION DEDICATION ACKNOWLEDGEMENTS ABSTRACT

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1 vi ABSTRACT Post tensioning flat slab are not complex where the construction technique, structure behavior and design are all simple. The tendon install provide a suspension system within the slab and the simple balancing load were used. The principle of designing post-tensioning flat slab is based on the parabolic tendon profile which exerts to upward pressure and balance to the downward loading. The installation of post tensioning system should be done by experience personnel who can handle the problems occurs while installing, stressing and grouting process. This paper presents the results of case studies on two post tensioned pre-stressed flat slabs in which save in using reinforcement, helps in deflection and also provide head clearance for Mechanical and Electrical components to run.

2 vii ABSTRAK Pascategangan papak rata merupakan teknik pembinaan, kelakuan struktur dan reka bentuk semua mudah. Tetulang pasca tegangan yang menyediakan sistem penggantungan dalam papak dan pengimbangan beban yang mudah digunakan. Prinsip reka bentuk post-penegangan papak rata adalah berdasarkan susuk tendon parabola yang mengenakan tekanan dan kira-kira untuk loading ke bawah. Pemasangan sistem penegangan pos harus dilakukan oleh kakitangan pengalaman yang mampu menangani masalah-masalah yang berlaku semasa proses pemasangan, tegangan dan menyalut. Kertas kerja ini membentangkan keputusan kajian kes di dua pos ditegangkan papak rata pra-tekanan yang menjimatkan dalam menggunakan tetulang, membantu dalam pesongan dan juga menyediakan ruang untuk laluan komponen Mekanikal dan Elektrikal untuk menjalankan.

3 viii TABLE OF CONTENTS CHAPTER TITLE PAGE DECLARATION DEDICATION ACKNOWLEDGEMENTS ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS LIST OF APPENDICES ii iv v vi vii viii xii xv xvii xviii 1 INTRODUCTION 1.1 Introduction Problem Statements Objectives of the project Scope of the project 3 2 LITERATURE REVIEW 2.1 Flat slab Components Analysis for Moment 8

4 ix Division of panels- without drop Shear Deflection Conventional Flat Slab Components Analysis for Moment Division of panels- without drop Shear Deflection Pre-stressed Flat Slab Components Analysis for moment Division of panels without drop Shear Deflection Pre-stressing for Structure Application of Prestressing Advantages of Prestressing Types of Prestressing Materials Equipments 24

5 x 3 DESIGN AND DETAILING 3.1 Introduction Project Descriptions 3.2 Design Basis Project Kementerian Dalam Negeri, Jalan Duta, Kuala Lumpur Building Specification Design and Detailing Project Institusi Perguruan Pengajian Bahasa Melayu, UM Building Specification Design and Detailing Typical Design Cases Post Tensioning Flat Slab Design 51 4 CONSTRUCTION 4.1 Construction of slab Post Tensioning Flat Slab Installation of Pre-stressing tendon and approach of pre-stressing forces Assembly of cables and Sheaths Preparation of tendon before tensioning Preparation of anchorage before tensioning Cutting of wires, strands and bars Tensioning Procedure Grouting of duct Handling and Storage of tendon Responsibilities 79

6 xi 5 RESULTS AND DISCUSSION 5.1 Problems and Solutions Costing Summary 83 REFERENCES 85 Appendices A - F

7 1 CHAPTER 1 INTRODUCTION 1.1 Introduction Post tensioning is a cast in situ method which applied stressing to the concrete after hardening compared to the pre tensioning method where stressing is apply before concreting. Post tensioning system is commonly used in flat slab with or without drop panel and generally supported without beams, by columns with or without flared column heads. The post tensioning applies to the buildings, bridges and tank. The application of post tensioning were widely used because of the decrease slab thickness with the longer span, reduce cracks and deflection, reduce number of beams, and provide a sufficient of height of building for installation of Mechanical and Electrical conduit thus allow significant reduction in building weight versus a conventional reinforced concrete building. Besides that, there is less material handling on site and reduce labor force and minimize site congestion. Post tensioning system is more economical compared to conventional method especially when fast construction cycle required. Design of post tensioning is used to control behavior of structure within a loading condition. As per design the post tensioning force can be applied at various stages during construction to offset permanent load. Post tensioning was classified as bonded and un-bonded which depending on the tendon duct filled with grout mortar. The grout mortar is used to avoid the corrosion.

8 2 The method of construction is not complicated process to apply this method in building construction without knowledge. From the observation, the construction method seams simple to assist a contractor to venture into the post tensioning methods. There is no harm to adopt post tensioning system in our design and construction practices. 1.2 Problem statement Flat slab floors are commonly used in buildings with moderate live loads (2.5 to 4.0 kn/m 2 ) such as general office blocks. There are also preferred in cases with large spans of slab or where higher head rooms are required for a particular storey height. When the span of the slab is in the excess of about six meters a substantially heavy reinforcement is needed. As an alternative, post tensioned prestressed flat slabs are adopted. However there is very limited knowledge and literature available on this type of slab. Although the design of such slab can normally be done, the construction and installation of the prestressing systems need to be understood. A good knowledge in this subject may unfold the advantages of the slab against the conventional and in a way or another provide some guidance to the designers. This has led to the execution of the present project. Besides that many engineering and design specialist do not understand the many option availability of post tensioning methods and refused to accept new construction technology. Thus, they force the people to limit the experience towards post tensioning construction design and techniques. The consequence of it, our building codes enforces has been slow to adapt the changes in available building materials and construction technique. The study has been made to overcome the problem among the engineering specialist and exposed the simplest way in constructing these methods to switch to the new construction technology.

9 3 1.3 Objectives of the project The objectives of the project are as follows: a b c d e f To design post tensioned flat slabs and conventional flat slab. To observe and monitor the construction of flat slab and the application of the post tensioning forces. To widen the knowledge regarding the installation for inspection of post tensioning work for post tensioning concrete floor including post- tensioning systems, materials and grouting. To understand the cause of problems this arises during the installation and construction. To compare various aspects of design and construction of conventional and post tensioned prestressing flat slabs. To show the considerable benefit and opportunities to the Malaysian for the used in construction area. 1.4 Scope of the project The project carried out case study and understanding about a) The design of flat slabs b) The design of prestressed flat slab c) The method of installation of post tensioning anchorage block d) The method of implementing prestressed flat slab in the building construction e) The results of elongation of strand

THE DESIGN AND CONSTRUCTION OF POST TENSIONED FLAT SLAB NURHIDAYAH BINTI ZAKARIA

THE DESIGN AND CONSTRUCTION OF POST TENSIONED FLAT SLAB NURHIDAYAH BINTI ZAKARIA A dissertation submitted in partial fulfillment of the requirements for the award of the degree of Master of Engineering