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Many countries have started to use post-tensioned (PT) concrete because of its sustainability and low cost. However, it is not quite popular in Sri Lanka as the required knowhow and technology are not available within the country. By introducing PT concrete to the country, unwanted costs and time overruns could be eliminated from the construction projects. This paper, therefore, aims to identify the suitability and acceptability of PT concreting for/in Sri Lanka.

An extensive literature review was first carried out to gather knowledge on PT concreting. The four case studies that followed it included eight semi-structured interviews and a document review. Ten expert interviews were conducted finally to strengthen the findings of the literature review and case studies. Cross-case analysis and NVivo 11 content analysis software were used to analyze the data gathered.

Findings reveal that PT concreting saves cost and time of construction and that it can have a control over the resources required for construction, which makes it environment-friendly. PT concreting allows thinner concrete sections, extended spans, stiffer walls that resist lateral loads and stiffer foundations that resist the effects of shrinking and swelling soils.

It is found that PT concreting is more suitable for the construction industry in Sri Lanka than traditional concreting.

This paper aims to understand the structural fire performance of two-way post-tensioned flat slabs, particularly their deformations and load-carrying mechanisms in fire, and to explore the behaviour of post-tensioned high-strength self-compacting concrete flat slabs with unbonded tendons in fire.

Four tests of post-tensioned high-strength self-compacting concrete flat slabs were conducted under fire conditions. Numerical modelling using the commercial package ABAQUS was conducted to help interpret the test results.

Two of the specimens with lower moisture contents demonstrated excellent fire resistance performance, while the others with slightly higher moisture contents experienced severe concrete spalling.

The test results were discussed in respect of thermal profiles, deflections, crack patterns and concrete spalling. The performance of post-tensioned high-strength self-compacting concrete flat slabs with unbonded tendons under fire conditions was better understood.

This study aims to investigate the influence of tendon layout, pre-stressing force, bond condition and concrete spalling on the structural behaviour of two-way post-tensioned flat slabs at elevated temperatures.

Fire tests of four scale specimens of two-way post-tensioned concrete flat slabs were performed and analysed. Three of them were provided with bonded tendons, while the other was unbonded for comparison. The fabrication of specimens, phenomena observed during testing, temperature distributions, deflections and occurrence of concrete spalling were examined.

Different degrees of concrete spalling observed at the soffit had significant effects on the temperature distribution and stress redistribution. This was the major reason for the progressive concrete spalling observed, resulting in loss of structural integrity and stiffness.

The structural behaviour of two-way post-tensioned concrete flat slabs at elevated temperatures is less understood compared to their one-way counterparts. Therefore, the present study has focused on the structural behaviour of two-way post-tensioned concrete flat slabs with bonded tendons in fire, a field in which relatively little information on experimental work can be found.

This study aims to determine the effects of three different carrier system materials (laminated wooden beams, post-tensioned concrete beams and steel beams) used widely in interior spaces on the perceptual evaluations of respondents.

The large opening Olympic swimming pool space was chosen as the research environment. A total of 376 university graduates participated. After experiencing the 360-degree virtual images of the experimental spaces, a “spatial perception” questionnaire was applied to these respondents.

The spaces using the laminated wood beams in the carrier system were perceived as warmer, lighter, more attractive, more spacious, more informal, closer, more well-planned, freer, simpler, more peaceful, more exciting, and uncrowded compared to the spaces that used post-tensioned concrete beams and steel beams. The architect respondents made more negative perceptual evaluations for all the adjective pairs compared to the respondents in the other professional groups. Respondents who were males, and in the 26–35 years of age group, perceived more positively the physical environmental factors of the virtual swimming pools compared to females, and the 36 years of age or above age group.

The results set forth that the structural elements of buildings, such as ceilings, walls and furnishings, were not only systematic elements used in the formation of the structure, they were also important environmental factors in the perceptual evaluation of the space.

The fire-safe structural design and construction of unbonded post-tensioned (UPT) flat plate concrete structures has recently come under debate in the UK, and questions are being raised regarding the response to fire of post-tensioned concrete slabs. Related to these concerns is the real world response of continuous UPT tendons inside such structures both during and after a fire, which is largely unknown and depends on many potentially important factors which are not currently accounted for in standard fire tests. Several credible concerns exist for UPT concrete structures in fire, most notably the potential for premature tendon rupture due to localized heating which may result from a number of possible causes (discussed herein). The research presented in this paper deals specifically with the time-temperature-stress-strength interdependencies of stressed UPT tendons under localized transient heating, as may be experienced by tendons in a real UPT building in a real fire. Nineteen high temperature stress relaxation tests on UPT tendons of realistic length and parabolic longitudinal profile are reported. It is shown that localized heating of UPT tendons is likely to induce premature tendon rupture during fire, even in structures which meet the prescriptive concrete cover requirements imposed by available design codes.

This is Part II of a two part paper dealing with the current state of knowledge of the fire-safe structural design and construction of unbonded post-tensioned (UPT) flat plate concrete structures. Part I provided detailed results of nineteen transient high temperature stress relaxation tests on restrained UPT tendons of realistic length and parabolic longitudinal profiles. Experimentation identified several credible concerns for UPT concrete structures in fire, most notably the potential for premature tendon rupture due to localized heating, which may result from a number of possible causes in a real structure. The real world response of continuous UPT tendons both during and after heating is largely unknown, and is dependent on factors which are not currently accounted for either in standard fire tests or by available prescriptive design guidance. This second part of the paper presents and applies a numerical model to predict the time-temperaturestress-strength interdependencies of stressed UPT tendons under localized transient heating, as may be experienced by tendons in a real concrete building in a real fire. The model is used, along with previously developed and validated computational models for heat transfer and prestress relaxation in UPT tendons, to assess existing prescriptive concrete cover requirements for UPT slabs. It is shown that localized heating of UPT tendons is likely to induce premature tendon rupture during fire, and that current prescriptive code procedures based on concrete cover alone are, in general, insufficient to prevent this. Based on the data presented it appears that minimum code prescribed concrete covers for UPT structures require revision if premature tendon rupture during fire is to be avoided.

Presents a non‐linear numerical model for the computations of post‐tensioned plane structures. Generally curved prestressing tendons and reinforcing bars are embedded into the concrete and they are modelled independently of the concrete mesh using one‐dimensional curvilinear elements. Among the losses which influence the decrease in the prestress force, it is possible to compute the losses caused by friction between tendons and the concrete, the losses which result from the concrete deformation and the losses in the anchorage zone. The computation for post‐tensioned structures is organized in phases: the phase preceding prestressing (Phase I), the prestressing phase (Phase II) and the phase following prestressing (Phase III). The load is applied incrementally until failure. The model is tested on a number of examples.

The paper illustrates a viaduct collapse due to corrosion phenomena. Moreover, a contribution to the issues related to both the control of existing structures and design methods to be followed for the construction of new buildings is provided.

The objectives were achieved by in situ observations and numerical analyses. The effects of corrosion phenomena are investigated, and the progressive collapse analysis is provided to be helpful in this case.

The damages induced by corrosion phenomena have caused the collapse of the viaduct taken in to account. The performed numerical analyses were able to reproduce the effects of corrosion in terms of reduction of wires diameter.

The research is limited to prestressed concrete viaduct with post-tensioned cables.

A monitoring plan, subdivided in several phases, is suggested, to avoid critical situations as these described.

The case study brought useful information on the effects of corrosion on the decks section, showing how the technology in post-tensioned cables is usually insidious and prone to the issues relating to corrosion of the wires

Ground movement is responsible for over 60 per cent of structural defects in low‐rise residential properties. Since 1971, insurance companies have been responsible for the significant rectification costs. Repair strategies are currently two‐fold, being determined by whether or not the foundations are underpinned. The Hoopsafe system uses a grid of post‐tensioned concrete beams, cast at foundation level, to restore the structural integrity of the property. The system can provide an alternative to traditional underpinning at an economic cost. Additional benefits include minimal disruption on site and short contract periods; the necessity for homeowners to vacate their properties is usually avoided. These benefits have been demonstrated by illustrative case studies. Professional consultants must consider all options to determine the most effective and appropriate repair technique. The Hoopsafe system can provide an alternative option in the selection process.

This suspension bridge, with its main span of 3,300 ft., is expected to be opened in 1963. It will be the largest in Europe and the fourth largest in the world. A number of interesting improved techniques will be used in protecting it from corrosion and, in particular, the post‐tensioning cables which anchor the side towers to the base rock are expected to last over a century.