This thesis presents the development and validation of a high ductility seismic resistant steel brace connector called the Yielding Brace System (YBS) that improves the earthquake performance of steel braced frame buildings. The connector is comprised of two steel castings which dissipate seismic energy through flexural yielding of specially designed triangular yielding fingers. In this body of work, the need for such a system is presented along with a summary of previously developed steel castings for enhanced earthquake performance of building structures. The development of the YBS concept is then discussed in detail and equations are developed to predict the elastic and plastic response of a YBS connector based on the geometry of the yielding fingers. The low-cycle fatigue life of the cast steel material used for the yielding elements of the YBS is characterized based on the results of several cyclic, small-scale yielding fingers tests and a low-cycle fatigue life prediction model is derived. Following this, the design of a prototype connector for the second storey brace of a fictitious six storey sample building located in Los Angeles is presented. This design is conducted using the low-cycle fatigue prediction model, the response prediction equations and non-linear finite element analysis. Results of four full-scale prototype tests are then presented. Two of the tests are axial tests of the device alone, while the other two are full-scale braced frame tests. Finally, the design of a 12-storey sample building is presented. This building design is then evaluated via non-linear time-history analysis using the FEMA P-695 methodology. The results from these analyses are then discussed and compared to a similar study conducted on the same building designed with buckling restrained braces. This work shows that the Yielding Brace System is a highly ductile, seismic resistant brace that can be used as an alternative to the buckling restrained brace with the potential to provide a stiffer structure with increased ductility.

OBJECTIVE: The objective of this study is to determine the different biological, psychological, and social factors that affect patient adherence in bracing treatment for adolescent idiopathic scoliosis. By comparing adherent and non-adherent bracing patients, we hope to gain insight into how to improve patient adherence in bracing as a means of primary treatment and to avoid secondary and tertiary treatments such as surgery. METHODS: Of the 19 patients (15 adherent, 4 non-adherent) who were examined for this study, the majority of them completed all psychosocial surveys at one time point in their bracing treatment. Patients answered surveys for multidimensional anxiety, generalized anxiety, pain-related fear and avoidance, pain catastrophizing, and quality of life. Quantitative sensory testing was performed on only 5 of the 19 patients at the time of writing. Sensory testing was conducted to gather information on thermal sensitivities and thresholds. Statistical t-test significance was determined for all surveys distributed to adherent and non-adherent bracing groups, and scaled T-scores were calculated for each survey measure to determine clinical significance. RESULTS: There were no statistically significant differences in any measures examined between adherent and non-adherent bracing patients. The only statistically significant difference was the number of hours of brace wearing, with the adherent group wearing their brace over 11 hours more than the non-adherent group (p < 0.0004). CONCLUSIONS: Because of the underpowered nature of this study, measures for multidimensional anxiety, generalized anxiety, pain-related fear and avoidance, pain catastrophizing, and quality of life should be reexamined for potential differences between adherent and non-adherent bracing patients. Quantitative sensory testing should be included as a measure of possible sensory differences between the two groups. A future study with a larger sample size may provide greater understanding into the motivations for bracing adherence in an effort to help patients avoid more invasive means of intervention in treating adolescent idiopathic scoliosis.

O trabalho analisa as forças atuantes no contraventamento de treliças triangulares de coberturas de madeira por meio de modelos numéricos computacionais. Os modelos foram confeccionados no sistema de análise estrutural Strap e consideram o funcionamento do contraventamento na estrutura tridimensional. Os valores máximos das forças obtidas nos modelos tridimensionais foram comparados aos valores mínimos indicados pelo método de estimativa da NBR 7190 (1997), este, baseado na instabilidade lateral do elemento contraventado. Os valores dos modelos tridimensionais também foram comparados aos métodos do Eurocode 5, da norma sul-africana SABS 0163 e aos valores propostos por Underwood (2000), por apresentarem formulação semelhante ao da NBR 7190 (1997). Os modelos representam galpões usuais na prática, com dimensões variando de 12 a 24 metros de vão; 24 a 96 metros de comprimento; 3, 4 e 6 metros de altura do pilar. Foram analisados para os tipos de treliça Howe e Pratt, para as classes de madeira C30 e C50 e para os tipos de telhas fibrocimento, metálicas e cerâmicas, materiais mais utilizados no Brasil. Os resultados mostram que as forças atuantes no contraventamento dos modelos tridimensionais são superiores aos valores obtidos pelo método da NBR 7190 (1997) e que valores obtidos pelos métodos propostos pelo Eurocode 5 e por Underwood (2000) apresentam-se mais seguros diante do funcionamento global da estrutura. / This work analyzes the forces acting on the bracing bars of triangular timber trusses by computational numerical models. The models are produced in the system of structural analysis Strap and consider the operation of bracing in the three-dimensional structure. The maximum forces obtained in the three-dimensional models are compared to the minimum values indicated by the estimation method of the NBR 7190 (1997), which is based on the lateral instability of the braced element. The values of three-dimensional models are also compared to the methods of Eurocode 5, the South African standard SABS 0163 and the values proposed by Underwood (2000). The models represent sheds with usual dimensions ranging from 12 to 24 meters wide, 24 to 96 feet long, and pillar 3, 4 and 6 meters tall. Are analyzed the Pratt and Howe types of truss, the timber classes C30 and C50 and the types of tiles: cement, metal and ceramics, materials most used in Brazil. The results show that the forces acting on the bracing of the three-dimensional models are greater than those obtained by the NBR 7190 (1997) and values obtained by methods proposed by the Eurocode 5 and Underwood (2000) provides more insurance on the overall functioning structure.

An arched structure provides an effective load carrying system for large span structures. When it comes to long span roof structures, timber arches are one of the best solutions from both structural and aesthetical point of view. Glulam arched structures are often designed using slender elements due to economic consideration. Such slender cross-section shape increases the risk of instability. Instability analysis of straight members such as beam and column are explicitly defined in Eurocode. However, for instability of curved members no analytical approach is provided in the code, thus some numerical method is required. Nonetheless, an approximation is frequently used to obtain the effective buckling length for the arched structures in the plane of arches. In this master thesis a linear buckling analysis is carried out in Abaqus to obtain an optimal effective buckling length both in-plane and out-of-plane for circular glulam arched structures. The elastic springs are used to simulate the overall stiffness of the bracing system. The results obtained by the FE simulations are compared with a simple approximation method. Besides, the forces acting on the bracings system is obtained based on 3D geometric nonlinear stress analysis of the timber trusses. Our findings conclude that the approximation method overestimates the effective buckling length for the circular glulam arched structures. In addition, the study indicates that the position of the lateral supports along the length of the arch is an important design aspect for buckling behaviour of the arched structures. Moreover, in order to acquire an effective structure lateral supports are needed both in extrados and intrados. Furthermore, instead of using elastic spring elements to simulate the overall stiffness of the bracing system, a full 3D simulation of two parallel arches was performed. It was shown that the springs are stronger than the real bracing system for the studied arch.

This thesis presents the results of an investigation of a multiple degree of freedom (MDOF) structure with hyperelastic bracing using nonlinear and incremental dynamic analysis. New analytical software is implemented in the investigation of the structure, and the study seeks to investigate the effectiveness of hyperelastic bracing as a seismic protection device. Hyperelastic braces incorporate a new idea of a nonlinear elastic material that gains stiffness as the brace deforms. Structural behaviors of particular concern for an MDOF frame are stability, residual displacement, base shear, and dispersion. The structure is analyzed under two ground motion records of varying content, and for two separate P-Delta cases of varying severity. Two sets of hyperelastic braces are investigated for their influence under the two ground motions and two P-Delta cases. Each scenario is analyzed using nonlinear dynamic analyses to investigate the response histories, and Incremental Dynamic Analysis (IDA) to investigate dispersion and the behavior of specific response measures as ground motion intensity increases. IDA curves are created for interstory drift and base shear for comparison between the two response measures. The research shows that the inclusion of hyperelastic braces in the MDOF frame improves the overall stability of the structure and reduces the amount of dispersion and residual displacement. The hyperelastic braces are shown to give positive performance characteristics while not detrimentally increasing system forces under regular service loads. The results highlight the benefit of the unique stiffening properties of hyperelastic braces as a seismic protection device. / Master of Science

Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.

Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.

Light-frame shearwall assemblies have been successfully used to resist gravity and lateral loads, such as earthquake and wind, for many decades. However, there is a need for maintaining the structural integrity of such buildings even when large openings in walls are introduced. Wood portal frame systems have been identified as a potential alternative to meet some aspects of this construction demand. The overarching goal of the research is to develop wood portal frame bracing systems, which can be used as an alternative or in combination with light-frame wood shearwalls. This is done through investigating the behavior of wood portal frames using the MIDPLY shearwall framing technique. A total of 21 MIDPLY corner joint tests were conducted with varying bracing details. Also, a finite element model was developed and compared with test results from the current study as well as studies by others. It was concluded from the corner joint tests that the maximum moment resistance increased with the addition of metal straps or exterior sheathings. The test results also showed a significant increase in the moment capacity and rotational stiffness by replacing the Spruce-Pine Fir (SPF), header with the Laminated Veneer Lumber (LVL) header. The addition of the FRP to the standard wall configuration also resulted in a significant increase in the moment capacity. However, no significant effect was observed on the stiffness properties of the corner joint. The FE model was capable of predicting the behavior of the corner joints and the full-scale portal frames with realistic end-conditions. The model closely predicted the ultimate lateral capacity for all the configurations but more uncertainty was found in predicting the initial stiffness.The FE model used to estimate the behavior of the full-scale portal frames constructed using the MIDPLY framing techniques showed a significant increase in the lateral load carrying capacity when compared with the traditional portal frame. It was also predicted using the full-scale FE model that the lateral load carrying capacity of the MIDPLY portal frame would increase with the addition of the metal straps on exterior faces. A parametric study showed that using a Laminated Strand Lumber (LSL) header increased the lateral load carrying capacity and the initial stiffness of the frames relative to the SPF header. The study also showed that there was an increase in the capacity if high strength metal straps were used. Doubling of the nail spacing at header and braced wall segment had a considerable effect on the lateral capacity of portal frame. Also, the initial stiffness was reduced for all the configurations with the doubling of the nail spacing at the header and braced wall segment in comparison with the reference frame.

The construction of the concourse is designed from steel.Construction was designed in 2 variants.The construction of the hall is radially curved in plan view with a circular sector on the longitudinal side.Roof structure consists of eight trusses at an axial distance of 9 m.Tracks are arched truss designed as a parallel.Trusses are designed to span 40m.Maximum ground clearance hall at the top is 14 meters.Letištní hala byla řešena v programu Scia Engineer 2014 a součástí je i výkresová dokumentace.

The main target is to design and asses the steel structure of a administartive multi-storey building. The steel structure is T shaped, with 30m span and 42m length. An analysis of two solutions of the supporting structure was performed. The first variant is consists of rigid bracing system. Trusses bracing in the second variant is an alternative solution. Both variants were compared and the amount of steel was found. The selected option was developed in greater details with static calculation, drawings and material report of steel.