Flexural behaviour of prefabricated prestressed concrete joists | |
| Author | Nuttawat Chutarat |
| Call Number | AIT Thesis no. ST-93-3 |
| Subject(s) | Strains and stresses Precast concrete construction |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | The aim of this research work was to develop a prefabricated prestressed joist used in a building system known as Self-Contained Housing Delivery System. The design of the prestressed joist was based on the serviceability limit state of Class 3 member which allowed a maximum crack width of 0.2 mm. A simple mechanical prestressing device was proposed for prestressing the wire. The load carrying capacities of the obtained prestressed joists were determined experimentally on the composite section between the joist and topping concrete slab. The testing objectives were to ensure the safety of the prestressed joists and determine the most appropriate section. The loss of prestress from the proposed mechanical prestressing device was observed. The cement content, number and position of the wires, and span length were considered as the main parameters in the experimental investigation. Test results showed that the proposed mechanical prestressing device was found to be satisfactory and could be adopted for practical use. The loss of prestress from the system was found to be less than 5%. Based on the maximum permissible computed deflection specified by ACI 318-85, the safety factors for the prestressed joists were found to be the range of 2.2-3.7 which are acceptable for practical purpose. The initial prestressing force and number and position of the prestress wires were found to be the main factors which affected the load carrying capacities and first crack load of the joist. The cement content of the joist concrete did not significantly change the flexural behaviour of the prestressed joist. A minimum of 300 Kg/m3 of cement could be used. For the joist used, the arrangement of prestressing wires one by one along the joist depth was recommended since it facilitated the prestressing and concrete casting. |
| Year | 1993 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pichai Nimityongskul |
| Examination Committee(s) | Worsak Kanok-Nukulchai ;Aoyagi, Yukio ;Lefebvre, Bernard G. |
| Scholarship Donor(s) | King's Scholarship |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1993 |