Currently there is a worldwide renaissance in timber building design. At the University of Canterbury, new structural systems for commercial multistorey timber buildings have been under development since 2005. These systems incorporate large timber sections connected by high strength post-tensioning tendons, and timber-concrete composite floor systems, and aim to compete with existing structural systems in terms of cost, constructability, operational and seismic performance. The development of post-tensioned timber systems has created a need for improved lateral force design approaches for timber buildings. Current code provisions for seismic design are based on the strength of the structure, and do not adequately account for its deformation. Because timber buildings are often governed by deflection, rather than strength, this can lead to the exceedence of design displacement limitations imposed by New Zealand codes. Therefore, accurate modeling approaches which define both the strength and deformation of post-tensioned timber buildings are required. Furthermore, experimental testing is required to verify the accuracy of these models. This thesis focuses on the development and experimental verification of modeling approaches for the lateral force design of post-tensioned timber frame and wall buildings. The experimentation consisted of uni-direcitonal and bi-directional quasi-static earthquake simulation on a two-thirds scale, two-storey post-tensioned timber frame and wall building with timber-concrete composite floors. The building was subjected to lateral drifts of up to 3% and demonstrated excellent seismic performance, exhibiting little damage. The building was instrumented and analyzed, providing data for the calibration of analytical and numerical models. Analytical and numerical models were developed for frame, wall and floor systems that account for significant deformation components. The models predicted the strength of the structural systems for a given design performance level. The static responses predicted by the models were compared with both experimental data and finite element models to evaluate their accuracy. The frame, wall and floor models were then incorporated into an existing lateral force design procedure known as displacement-based design and used to design several frame and wall structural systems. Predictions of key engineering demand parameters, such as displacement, drift, interstorey shear, interstorey moment and floor accelerations, were compared with the results of dynamic time-history analysis. It was concluded that the numerical and analytical models, presented in this thesis, are a sound basis for determining the lateral response of post-tensioned timber buildings. However, future research is required to further verify and improve these prediction models.

Este trabalho trata do projeto e da construção de edifícios de andares múltiplos com estrutura formada por perfis de aço e está ligado a duas áreas distintas da engenharia: a acadêmica e a prática. Para a acadêmica fornece uma quantidade de informações que permitem o desenvolvimento de diversas pesquisas sobre o assunto. Para a área prática fornece parâmetros que permitem discutir a viabilidade desta modalidade construtiva e as informações mínimas para o desenvolvimento do projeto e orientação da construção. Para tanto, o conteúdo foi distribuído em 6 capítulos, onde no primeiro é feita uma análise da evolução destas construções, sob o ponto de vista arquitetônico e apresentadas algumas divergências quanto ao ensino e a aplicação desta modalidade construtiva. No segundo capítulo são discutidos alguns aspectos construtivos ligados aos sistemas estruturais já utilizados, a racionalização por ocasião do projeto e o comportamento frente a incêndios. No terceiro capítulo são analisados alguns aspectos estruturais, como os comportamentos estático, dinâmico, de segunda ordem e a influência da rigidez das ligações na rigidez global da estrutura. No quarto capítulo é abordado o sistema estrutural aporticado e desenvolvido o projeto de um edifício, com vinte pavimentos, que permite analisar o comportamento dos seus elementos constitutivos. No quinto capítulo são analisados diversos sistemas estruturais aplicáveis a estas construções, como os aporticados; os com núcleos resistentes; em \"outrigger\"; e os tubulares. Finalmente, no sexto e último capítulo apresentam-se as recomendações e conclusões consideradas pertinentes e alguns temas para pesquisas posteriores. / The aim of this work is the design and construction of multi-storey buildings with steel structures linked to two different fields of the engineering: theorical and practical. For the formar it gives a great deal of information that allows the development of several researches about the topic. For the later it gives parameters which permit discussing the viability of this kind of system, and the least information for the development of the design and guidance of the construction. For this purpouse the content of this work was divided in six chapters, starting with an analysis of the evolution of these buidings on the architectonic point of view and also shows some disagreements related to teaching and the use of this kind of system. In the second one, some constructive aspects linked to usual structural systems are showed, the rationalization during the projet and the behaviour facing tires are discussed. The third chapter deals with some structural aspects as static and dynamic basis of second order and the influence of the stiffness of conections to determine the global stiffness of the structure. In the fourth chapter the complete analysis of the framed structure analysis in a 20 storey-building was developed. The fifth chapter discusses some alternative proposals to the structural system of the building treated in the late chapter; those with a resistent core system, an outrigger and the tube shaped structure. Finally, in the last chapter the remarks and conclusions are presented and some topics for posterior researches are suggested.

Estates of multi-storey housing present some of the most intractable problems for urban policy. Socially, many are characterised by a complex of deprivation. Physically, they often suffer from serious technical problems and poor environmental quality. This study traces the development of multi-storey housing from its early beginnings in the 19th century to the period from the mid-1950s to the early 1970s when most of the contemporary legacy of estates was built. In this period, it is suggested, the concentration on 'low cost' led to the poor design of access systems, the use of untried mass-production techniques and the virtual elimination of social facilities. All these economies sowed the seeds of the social rejection and degeneration that was to follow. The central question is whether such estates can be successfully modernised -or whether the only solution is to demolish them. In seeking an answer the various responses of social landlords are analysed. It emerges that the older, smaller estates can be effectively adapted to provide good housing. The large scale, more recent estates, however, have proved more resistant to improvement. Despite the fact that government has increasingly targeted the problem estates of the 1960s and 70s, many improvement schemes have met with limited success. Drawing on an analysis of past practice, a 'model of regeneration' is defined. This concentrates on the need for tenant participation; on the importance of design solutions which are both technically and socially appropriate; and on management which is sensitive to local needs. This model was tested through case studies on recent improvement schemes. From the results, conclusions are drawn about the value of the model and the prospects for regenerating the various types of multi-storey housing Finally, a strategic approach is defined which can re-form the estates and re-integrate them into the mainstream urban environment.

Este trabalho trata do projeto e da construção de edifícios de andares múltiplos com estrutura formada por perfis de aço e está ligado a duas áreas distintas da engenharia: a acadêmica e a prática. Para a acadêmica fornece uma quantidade de informações que permitem o desenvolvimento de diversas pesquisas sobre o assunto. Para a área prática fornece parâmetros que permitem discutir a viabilidade desta modalidade construtiva e as informações mínimas para o desenvolvimento do projeto e orientação da construção. Para tanto, o conteúdo foi distribuído em 6 capítulos, onde no primeiro é feita uma análise da evolução destas construções, sob o ponto de vista arquitetônico e apresentadas algumas divergências quanto ao ensino e a aplicação desta modalidade construtiva. No segundo capítulo são discutidos alguns aspectos construtivos ligados aos sistemas estruturais já utilizados, a racionalização por ocasião do projeto e o comportamento frente a incêndios. No terceiro capítulo são analisados alguns aspectos estruturais, como os comportamentos estático, dinâmico, de segunda ordem e a influência da rigidez das ligações na rigidez global da estrutura. No quarto capítulo é abordado o sistema estrutural aporticado e desenvolvido o projeto de um edifício, com vinte pavimentos, que permite analisar o comportamento dos seus elementos constitutivos. No quinto capítulo são analisados diversos sistemas estruturais aplicáveis a estas construções, como os aporticados; os com núcleos resistentes; em \"outrigger\"; e os tubulares. Finalmente, no sexto e último capítulo apresentam-se as recomendações e conclusões consideradas pertinentes e alguns temas para pesquisas posteriores. / The aim of this work is the design and construction of multi-storey buildings with steel structures linked to two different fields of the engineering: theorical and practical. For the formar it gives a great deal of information that allows the development of several researches about the topic. For the later it gives parameters which permit discussing the viability of this kind of system, and the least information for the development of the design and guidance of the construction. For this purpouse the content of this work was divided in six chapters, starting with an analysis of the evolution of these buidings on the architectonic point of view and also shows some disagreements related to teaching and the use of this kind of system. In the second one, some constructive aspects linked to usual structural systems are showed, the rationalization during the projet and the behaviour facing tires are discussed. The third chapter deals with some structural aspects as static and dynamic basis of second order and the influence of the stiffness of conections to determine the global stiffness of the structure. In the fourth chapter the complete analysis of the framed structure analysis in a 20 storey-building was developed. The fifth chapter discusses some alternative proposals to the structural system of the building treated in the late chapter; those with a resistent core system, an outrigger and the tube shaped structure. Finally, in the last chapter the remarks and conclusions are presented and some topics for posterior researches are suggested.

This thesis presents an analytical method based on classical matrix methods for computing the dynamic response of elastic-plastic multi-storey building frames. The method developed is comparatively simple and is of much use for building frames having large number of storeys. By this method, response of multi-storey build­ings could be calculated on high-speed digital computers of high storage capacity. The computer program developed saves huge storage locations and thus makes it possible to analyze multi-storey frames which till now were con­sidered as very difficult. Dynamic response of a two-storey and six-storey frame are shown to demonstrate the utility of the method. / Thesis / Master of Engineering (ME)

With the advancement in knowledge of inelastic response of structures, the design and construction practices of reinforced concrete buildings have been changing worldwide. Most of the codes are incorporating the near-fault factors and performance based designs in the seismic codes. However, further investigation is needed to identify the physical behaviour of multi-storey buildings to near-fault ground motions. At present, quantitative evaluation of response and its mitigation to near field ground motions is a popular topic in earthquake engineering field. The present study discusses the inelastic response of symmetric and asymmetric multi-storey buildings to near-fault ground motions. The possibility of design approach is based on ‘expendable top storey’ for the multi-storey RC- buildings to near field records. If such behaviour is feasible one can conceive of a structure whose top storey is permitted and designed to undergo large inelastic deformations while reducing damage in the lower storey. The concept was first proposed in an earlier research (RaghuPrasad, 1977). Such a concept juxtaposes the often-mentioned ‘soft first storey’ concept. Further in this report, the performance evaluation of multi-storey buildings near Chiplun fault in Mumbai, India is also discussed. The thesis is organized in the following chapters: Introduction in Chapter-1 contains detailed literature review on inelastic response of symmetric and asymmetric buildings, response of buildings to near-fault records, elastic and inelastic vibration absorber concepts and performance based designs. The literature reveals that considerable amount of research has been carried out on the elastic, inelastic response of structures and vibration absorber concepts to ordinary ground motions. Recently, the effect of near field ground motions on the response of multi-storey buildings is gaining much importance. Most of the research publications are available on response of symmetric buildings subjected to near field ground motions. But many problems are yet to be investigated. They are, identification of important ground motion parameters in near fault records, vibration absorber concepts and torsional response of structures subjected to pulse type ground motions. These problems are clearly mentioned in the recently published state-of-the-art review by Shuang and Li-Li (2007). In this report an attempt has been made to solve these problems. Effect of near-fault ground motions on symmetric multi-storey buildings in Chapter-2, describes simplified non-dimensionalized equations of motion to study the response behaviour of multi-storey buildings to near fault records. The non-dimensionalized equations of motion are expressed in terms of near fault ground motion parameters. The objective is to find a relation between ductility demand and near field ground motion parameters through neural network approach. For this a neural network modeling was done to predict the ductility demand in terms of peak ground acceleration, peak ground velocity, epicentral distance and pulse period of the near field ground motion. A thorough sensitive analysis is carried out, to ascertain which parameters are having maximum influence on ductility demand. In this chapter further, a comparative study is made on the inelastic seismic response of multi-storey buildings to pulse type and non pulse type ground motions. The study shows that, it is necessary to consider the effect of near fault ground motions separately and make provisions for the design in the codes of practice accordingly. Vibration absorber effect in multi-storey buildings in chapter-3, discusses the behaviour of top storey as a vibration absorber during near field ground motions. For this purpose, a five storey symmetric building model is considered as an example problem to demonstrate the effectiveness of the proposed concept. Response of the structure is obtained for the various combinations of absorber storey parameters such as mass ratio, frequency ratio and yield displacement ratio. Here mass ratio means mass of the absorber storey to that of the bottom storey and similarly for the frequency and yield displacement ratios. Observing the storey-wise variation of these responses, we can say that for a range of mass ratios, frequency ratios and yield displacement ratios, the inelastic response of top storey is large compared to the lower storeys. This range is termed as ‘effective range’. Further, in this range the top storey absorbs the vibration energy of the structure by keeping the lower storeys in elastic state i.e. acts as a vibration absorber. The top storey can also be termed as ‘expendable top storey’. Effect of near-fault ground motions on asymmetric multi-storey buildings in Chapter-4, discusses the inelastic response of asymmetric buildings to single horizontal component and two horizontal components of near fault ground motions viz., fault normal and fault parallel components. For numerical investigations eight building models are considered. Eccentricity has been created by keeping the stiffness and mass centre separately. The building models are subjected to strong motion records of Imperial Valley Array-5 (1979) and Northridge-Sylmar (1994). A detailed study on the effect of base shear strength, eccentricity and pulse period of near fault ground motions on the response is investigated. Performance of multi-Storey buildings in Chapter-5, reported a detailed procedure for the performance evaluation of structures. The procedure is applied to find the performance evaluation of multi-storeyed buildings located in near fault region. Chiplun fault in Mumbai, India has been chosen for the study because several features of that fault are clearly published (RaghuKanth and Iyengar, 2006). Results of performance evaluation of five and ten storeyed symmetric buildings with and without infill panels are studied. Ground motion records consistent with the hazard spectrum for the design are considered. The performance of the building near the Chiplun fault in Mumbai, India shows operational under UHS-500 (uniform hazard spectrum) event and it collapses when the building is exposed to UHS-2500 record. The thesis is concluded in Chapter-6 with an overall summary of the report and suggestions for further scope of the work.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2006. / The predominately manual, time-consuming and error-prone procedure currently used in engineering offices for the calculation of preliminary column forces in multi-storey buildings constitutes the motive for the research described in this study. Identifying the current procedure as in need of improvement, techniques and prototype software posing a semi-automated alternative, are developed. Influence areas used for load-assignment are established with the use of a Voronoi diagram calculated for a specific floor geometry. The forces transferred to the columns are based solely on the size of the influence areas thus calculated. The definition of the floor geometry, as well as the definition of loads and other necessary input parameters, are performed in a CAD-system, into which the Voronoi functionality is integrated. The accuracy of the forces obtained with the implemented procedure and, consequently, the accuracy of the forces as they are calculated in current practice, is determined through comparison with the results of finite element analyses. The comparative analysis of a sample of typical floor geometries allows an evaluation of the results and the identification of tendencies observed regarding the errors obtained. It is concluded that calculating column forces based on influence areas, i.e. solving a geometrical problem without taking any stiffness properties into account, is unsafe. The implication hereof is twofold. Firstly, it serves as a warning concerning the technique currently used in practice and secondly, it steers the investigation in the direction of a finite element analysis: using the influence areas as a basis for automatic meshing, a semi-automated analysis can be performed relatively inexpensively, using plate elements.

Implementation of intensive forestry (fertilization, cultivation of non-native tree species, and clone cultivation) on part of the forested land area in Sweden and an increased construction of wood-framed multi-storey buildings can contribute to reduce the net carbon dioxide emissions of the built environment. This thesis evaluates the acceptance of and interest in intensive forestry and multi-storey wood frames among different actors, and some of the underlying reasons for their approach. The results of quantitative and qualitative studies among members of the general public, private forest owners, architects, and contracts managers in Sweden are presented in six different papers. Both intensive forestry and multi-storey wood frames lack sufficient acceptance and compliance with relevant institutions such as priorities, norms, and regulations in the eyes of the studied actors. The acceptance of intensive forestry would be larger among members of the general public if they would perceive such practices to have less negative environmental effects and perceive a greater need to increase forest growth. Among the private forest owners, the interest to cultivate non-native tree species would be larger if there were more positive attitudes towards the economic consequences. Architects and contracts managers associate multistorey wood frames with several disadvantages and uncertainties, primarily with respect to fire safety, stability, durability, and sound proofing. The contracts managers’ perceptions have stronger implications for the prospects for wood frames, than the architects’ perceptions do. Promotional activities aimed to change such perceptions may improve the prospects for more wood framed multi-storey buildings in Sweden. The path dependency of Swedish multi-storey construction however implies that such activities are not enough for multi-storey wood frames to diffuse to greater extent. Broader changes to the wider context of the decisions taken in construction projects, e.g. to policy or economic environments, which change the priorities of the construction industry actors, are needed.

The environmentally friendly and high performance multi-storey LVL timber system developed at the University of Canterbury (UC) consisting of post-tensioned frames and shear walls is referred to as the Pres-Lam system. It is possible that this structural system has the ability to increase productivity and reduce construction costs when compared with concrete and steel construction materials. As the Pres-Lam system is a new technology, the actual construction time and cost are still unknown. The outcome of this research will add value to the construction industry and encourage the industry to consider the Pres-Lam system for future projects. Previous research has shown that construction using this type of structural system is feasible for multi-storey buildings. In case study (1), this research revisited the research done for the actual Biological Sciences building under construction at the University of Canterbury based on the latest information available from the UC timber research team. This research compared the construction time and cost of three virtual buildings (Pres-Lam, Concrete and Steel) for Case Study (1). The research has been able to optimise the performance of the Pres-Lam system having increased open spaces with large column spacing. The proposed fully prefabricated double “T” timber concrete composite (TCC) floor system was used and found to reduce construction time. This has also shown that the LVL components in the Pres-lam system can be fully prefabricated at a factory. In case study (1), the predicted estimated construction time for the structural system was 60 working days (12 weeks) as compared to the concrete structure which required 83 working days. In the construction time analysis only the construction time of the structural building portion was compared instead of the overall construction time of the building project. The construction cost estimation for the concrete, steel and optimised Pres-Lam overall buildings including claddings and architectural fittings were produced and compared. The construction cost analysis concluded that the construction cost of the Pres-Lam building has been estimated to be only 3.3% more than the steel building and 4.6 % more than the concrete building. In case study (2), this research evaluated the deconstructability of the Pres-Lam system and found that the Pres-Lam system was potentially a very sustainable building material where 90% of the deconstructed materials can be recycled and reused to construct a new office building at the University of Canterbury. The reconstruction time of the STIC office building has been predicted to be 15 weeks and the estimated cost for the reconstruction to be $260,118. This will be used for future construction planning, monitoring and control.

See appended files.