Master of Science / Department of Architectural Engineering and Construction Science / Donald J. Phillippi / Special moment resisting frames (SMRF) are intended to protect the structure from earthquake motions through a ductile inelastic response. This thesis evaluates the performance of reinforced concrete SMRFs with an emphasis on the second level beams. Due to previous research, it is concluded that two-dimensional finite element analyses (2D-FEA) and three-dimensional finite element analyses (3D-FEA) have different results when evaluating the same structure. Due to this, the thesis used a 3D-FEA to analyze frames based on Design Example 7 in the 2006 IBC Structural/Seismic Design Manual (Appendix A). While looking at the frame as a whole, the first of two parametric studies was performed over the columns. Using LS-DYNA the columns’ forces, displacement, moment, and curvature were evaluated. From these results, it was concluded that in SMRF, columns are not acting per current design assumptions due to the elongation of beams. Using the knowledge gained in the first parametric study, a second parametric study was performed on the second level floor beams. Focusing on the beam elongation, this thesis evaluates multiple frames with different load combinations using LS-DYNA to find the displacement of the reinforcement in the beams. With the results, an equation to calculate the elongation of beams was proposed, as well as an average percentage of the elongation in reinforced concrete SMRF. The equation and average percentage of elongation aim to provide a standard design consideration for the elongation of beams.

The topic of this thesis is pre-welding process specification for heat reisisting T24 steel with TIG method. This is concerned welding waterwalls during construction electrical steam boilers. The main advantage T24 steel, except high heat resistance, is T24 doesn´t need to pre-heating neither post-welding heat treatment. Two tubes from T24 steel was flash welding and evaluating weld metal with several tests in this experiment. ALSTOM Power, s.r.o is submitter of this project.

A continuous load path in a structure is always the best way to transmit the load from the upper story to the foundation. However, there is a tradition of using irregular shapes of structures nowadays to enhance the aesthetic, make a terrace, or for getting sunlight. This irregular shape disrupts the continuous load path of the structure and there is the formation of a high-stress zone in the structure which may lead to failure in case of extreme events. During the event of an earthquake, a structure that has an irregularity in its mass, stiffness, and strength suffers more damage as compared to its regular counterpart. So, we need to pay more attention while designing the irregular structure so that it can withstand the force acting on it and ensure the safety of people. So, in this thesis, the seismic response of structures with vertical irregularity is studied. For this purpose, the fundamental time periods of the structures with vertical irregularity are studied and compared with their regular structure. The obtained result is compared with the approximate fundamental period, Ta, given by ASCE/SEI 7-16. Also, the location of critical columns which has the highest load ratio is studied and designed.

Syftet med denna uppsats var att undersöka hur motståndsläsning eller motströmsläsning (resisting reading) kan användas som verktyg i tolkning av tre svenskspråkiga normkritiska sagobilderböcker; Alexander Janssons, Sofia Jensfeldts och Silvy Strands Rödluvan (2018), Askungen (2018) och Skönheten & Odjuret (2021). Dessa tre sagobilderböcker ingår i Moderna sagor-serien som publicerats av OLIKA förlag AB. Med hjälp av text- och bildanalyser utifrån ett genusperspektiv ville jag undersöka vilka genusstrukturer och normkritiska perspektiv dessa tre barnböcker visar upp. I anknytning till detta undersökte jag hur tolkning av normkritiska sagor med hjälp av motståndsläsning och -skrivande som en del av litteraturundervisning kan bidra till undervisning av normkritik och demokrati i den svenska skolan. Resultatet visar att läsande och skrivande mothårs kan inkluderas i undervisning av litteratur exempelvis vid modersmålsundervisning där fokus ligger i normkritik och samhällets demokratiska värderingar.

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A series of full-scale beam-to-column moment connection tests were completed to determine the effects of powder actuated fasteners (PAF) and puddle welds on the seismic behavior of steel moment connections.  In seismic regions, PAF are currently prohibited in the connection region (referred to as the protected zone) due to the concern of low-cycle fatigue fracture.  There is almost no information available in the literature regarding the seismic behavior of moment connections with PAF or puddle welds. Full-scale connection testing is the most accurate way to investigate the behavior of different moment connections with common defects and fasteners applied in the protected zone.  However, it is cost prohibitive to conduct full-scale testing programs that are sufficiently comprehensive to investigate a wide range of defect types, severity, and locations.  For this reason, it is desired to develop alternative methods of investigation.  A finite element (FE) model capable of simulating both the global deformation patterns and local buckling effects in a moment connection has been developed.  Validated FE models will allow for further evaluation through numerical simulation of additional configurations.  Furthermore, alternate, more economical, test configurations to experimentally investigate the effect of defects on steel moment connections were explored.  This report discusses the full-scale test setup, results and analysis of completed experimental testing, the development of an FE connection model, and the preliminary development of alternate test configurations. / Master of Science

The buildings that are designed according to the building codes generally perform well at severe performance objectives (like life safety) under high earthquake hazard levels. However, the building performance at low performance objectives (like immediate occupancy) under low earthquake hazards is uncertain. The motivation of this research is to modify the design and detailing rules to make the traditional systems perform better at multi-level hazards. This research introduces two new structural steel systems: hybrid Buckling Restrained Braced Frames (BRBF) and hybrid steel Moment Frames (MF). The "hybrid" term for the BRBF system comes from the use of different steel material including carbon steel (A36), high-performance steel (HPS) and low yield point (LYP) steel. The hybridity of the moment frames is related to the sequence in the plastification of the system which is provided by using weaker and stronger girder sections. Alternative moment frame connections incorporating the use of LYP steel plates are also investigated. The hybrid BRBF approach was evaluated on seventeen regular (standard) frames with different story heights, seismic design categories and building plans. By varying the steel areas and materials in the BRB cores, three hybrid BRBFs were developed for each regular (standard) frame and their behavior was compared against each other through pushover and incremental dynamic analyses. The benefits of the hybridity were presented using different damage measures such as story accelerations, interstory drifts, and residual displacements. Collapse performance evaluation was also provided. The performance of hybrid moment frames was investigated on a design space including forty-two moment frame archetypes. Two different hybrid combinations were implemented in the designs with different column sections and different strong column-weak beam (SC/WB) ratios. The efficiency of the hybrid moment frame in which only the girder sizes were changed to control the plastification was compared with regular moment frame designs with higher SC/WB ratios. As side studies, the effect of shallow and deep column sections and SC/WB ratios on the moment frame behavior were also investigated.   In order to provide adequate ductility in the reduced capacity bays with special detailing, alternative hybrid moment frame connections adapting the use of low strength steel were also studied. / PhD

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No / This study explores the lateral deflections of diagonal braces in concentrically-braced earthquake-resisting frames. The performance of this widely-used system is often compromised by the flexural buckling of slender braces in compression. In addition to reducing the compressive resistance, buckling may also cause these members to undergo sizeable lateral deflections which could damage surrounding structural components. Different approaches have been used in the past to predict the mid-length lateral deflections of cyclically loaded steel braces based on their theoretical deformed geometry or by using experimental data. Expressions have been proposed relating the mid-length lateral deflection to the axial displacement ductility of the member. Recent experiments were conducted on hollow and concrete-filled circular hollow section (CHS) braces of different lengths under cyclic loading. Very slender, concrete-filled tubular braces exhibited a highly ductile response, undergoing large axial displacements prior to failure. The presence of concrete infill did not influence the magnitude of lateral deflection in relation to the axial displacement, but did increase the number of cycles endured and the maximum axial displacement achieved. The corresponding lateral deflections exceeded the deflections observed in the majority of the previous experiments that were considered. Consequently, predictive expressions from previous research did not accurately predict the mid-height lateral deflections of these CHS members. Mid-length lateral deflections were found to be influenced by the member non-dimensional slenderness ( ) and hence a new expression was proposed for the lateral deflection in terms of member slenderness and axial displacement ductility. / TATA Steel