Pushover Response of Multi Degree of Freedom Steel Frames

Seismic codes use the behaviour factor to consider the ductility and the structure's non-linearity to improve the system's overall performance. Generally, Steel moment-resisting frames are characterized by a relatively high period showing high deformability and, foreseen that with stringent damageability criteria, the adopted behaviour factor might not optimally be utilized for achieving better performance of the frames. The design is generally governed by stiffness, leaving behind a complex structural system where the capacity design rules are disturbed and therefore necessitates to relax the drift limits for such frames. Given this and with extensive parametric analysis, the current paper aims to examine the behaviour factor of steel Moment Resisting Frames (MRFs). The parametric analysis has been conducted on rigid steel MRFs of 9, 7, and 5 storeys with bay 4 different bay widths of 9.15 m, 7.63 m, 6.54 m, and 5.08 m. Perimeter frame configuration has been designed using 4 different behaviour factors (q = 6.5, 4, 3, and 2) for a total number of 144 cases. Static nonlinear analysis has been conducted, and consequently, the behaviour factors have been examined. It has been observed that compatibility is required while choosing the drift limit for an assumed ductility class of the code. Doi: 10.28991/cej-2020-SP(EMCE)-08 Full Text: PD

Utilization of Marble Wastes in Clay Bricks: A Step towards Lightweight Energy Efficient Construction Materials

Marble dust is one of the hazardous byproducts of marble-processing factories and requires planned disposal. Its beneficial use as a construction material will add to the sustainability, and most importantly, might overcome the burden of marble waste disposal. However, the use of marble dust in concrete has a negative impact. Therefore, this research examines various properties related to the utilization of such material in ceramic clay, and therefore its effects on the use of clay bricks are investigated. The research activity covers the categorization of marble dust powder from three different sources: Ziarat in Mohmand Agency, Buneer, and Mullagori (Pakistan). Its utilization in different proportions preparation of bricks is also addressed. Through the partial replacement of clay with marble dust from 0 to 30% by weight with amplification of 5%, seven mix designs are examined. The test result includes Bulk density, water absorption, porosity, thermal insulation, and strength. The partial replacement of clay with marble dust reduced its weight, strength and increased its porosity, water absorption, and thermal insulation. Furthermore, the utilization of marble powder in bricks minimizes soil erosion and reduces pollution to the environment. Doi: 10.28991/cej-2021-03091738 Full Text: PD

Design and performance testing of a skylight in Qatar

The current paper deals with a case study on façade industry with the purpose to be useful for the engineers involved in the structural and architectural design of curtain walls. The research activity has been based on both the structural calculation and the experimental test on the Le Boulevard skylight in Doha (Qatar), measuring 36m by 1Sm in plan, located at a height of about 42 m and subjected to a wind load of 1.7 KPa. The skylight, composed of steel rectangular curved tubes, glass and aluminium sandwich panels, is designed for a basic wind speed of 25 m/s as per Qatar Construction Standards. Two types of steel frames have been designed, one to support both the glazing and aluminium sandwich panel, and another to transfer all the loads to the main structure. Subsequently, a performance testing on a specimen extracted from the skylight has been performed. The test was carried out by Aluminium Technology Auxilliary Ind. (ALUTEC) on a specimen having length and width of 6.625 m and 3.315 m, respectively. The assessment procedures have been carried out following the "ASTM E2S3", "ASTM E331" and "ASTM E330" standards. The d within the acceptable limits for the skylight components specified by the standards and required by the project specification

Aluminium framing members in facades

Curtain wall systems are considered as envelop of a building, generally made of a lightweight material such as aluminium. The curtain wall façade does not carry any weight from the building, rather it transfers loads that are incident upon it to the main building structure through connections with floors or columns. This paper addresses some key issues in satisfying the respective limit state design checks. Two mullion profiles 85mm and 125mm deep of three manufacturers are analysed showing that the different extrusions of mullion profiles does not have any drastic effect on its structural behavior. Due to the versatility and lightweight, aluminum has many advantages when used as a curtain wall framing material, but it has the distinct disadvantage of being three times more deformable than steel. Therefore, the fulfillment of serviceability limits is an important issue when designing the framing members, in order to avoid damage of connected glasses. Also, the importance of connections and steel insert are highlighted. Finally, some completed and in-progress ALUTEC projects with different curtain wall systems are presented. The paper is therefore interesting for the Façade Engineers involved in the design of curtain walls

Mechanical, Durability and Microstructure Analysis Overview of Concrete Made with Metakaolin (MTK)

Metakaolin (MTK) has received a lot of interest in the past two decades as a supplemental cementitious ingredient. MTK is actively being utilized in concrete and there is a large body of literature on the characteristics of concrete containing MTK. A rigorous evaluation of the use of MTK in concrete, however, is lacking, which is required to better know its (MTK) benefits, mechanisms, past and current progress. As a result, the objective of this study is to deliver an overview of MTK utilized in concrete. The physical and chemical characteristics of MTK, as well as the hydration, workability, mechanical qualities, hydration durability, and microstructure analysis of MTK-based concrete, are discussed. A comparison of the findings of diverse literature is presented, as well as some key recommendations. The findings suggest that adding MTK to concrete enhances certain characteristics, particularly mechanical capabilities, but decreases concrete flowability. Improvement in the durability of concrete with MTK was also observed but, for this, less information is available. For optimal performance, the right dosage is crucial. The typical ideal range is between 10 to 20% by weight of the binder. Further research gaps into the characteristics of concrete containing MTK are also recommended

Seismic Capacity Assessment of Confined Brick Masonry Building: An Experimental Approach

Brick masonry is widely used for building construction throughout the world. However, unreinforced brick masonry buildings performed poorly in the 2005 Kashmir earthquake, in Pakistan, resulting in a decline in the use of brick masonry. In order to investigate and quantify the performance of brick masonry against the seismic forces by confining it through typical stiffer, line elements (column and beams), a full-scaled room model of an area 3048 × 3658 mm (10 × 12 ft) and height of 3353 mm (11 ft) was constructed using confined brick masonry. The model was tested under quasistatic loading system. Crack pattern was noted at the end of each loading cycle. The response of the model was interpreted through a hysteresis curve, which was then idealized by a bilinear curve. A comparison of the results has been made with four different studies done on the similar model made of unreinforced brick masonry before and after retrofitting and unreinforced concrete block masonry before and after retrofitting previously tested at the same testing facility

ABET Accreditation During and After COVID19 - Navigating the Digital Age

Engineering accreditation agencies and governmental educational bodies worldwide require programs to evaluate specific learning outcomes information for attainment of student learning and establish accountability. Ranking and accreditation have resulted in programs adopting shortcut approaches to collate cohort information with minimally acceptable rigor for Continuous Quality Improvement (CQI). With tens of thousands of engineering programs seeking accreditation, qualifying program evaluations that are based on reliable and accurate cohort outcomes is becoming increasingly complex and is high stakes. Manual data collection processes and vague performance criteria assimilate inaccurate or insufficient learning outcomes information that cannot be used for effective CQI. Additionally, due to the COVID19 global pandemic, many accreditation bodies have cancelled onsite visits and either deferred or announced virtual audit visits for upcoming accreditation cycles. In this study, we examine a novel meta-framework to qualify state of the art digital Integrated Quality Management Systems for three engineering programs seeking accreditation. The digital quality systems utilize authentic OBE frameworks and assessment methodology to automate collection, evaluation and reporting of precision CQI data. A novel Remote Evaluator Module that enables successful virtual ABET accreditation audits is presented. A theory based mixed methods approach is applied for evaluations. Detailed results and discussions show how various phases of the meta-framework help to qualify the context, construct, causal links, processes, technology, data collection and outcomes of comprehensive CQI efforts. Key stakeholders such as accreditation agencies and universities can adopt this multi-dimensional approach for employing a holistic meta-framework to achieve accurate and credible remote accreditation of engineering programs

A Comprehensive Review on the Ground Granulated Blast Furnace Slag (GGBS) in Concrete Production

In the last few decades, the concrete industry has been massively expanded with the adoption of various kinds of binding materials. As a substitute to cement and in an effort to relieve ecofriendly difficulties linked with cement creation, the utilization of industrial waste as cementitious material can sharply reduce the amount of trash disposed of in lakes and landfills. With respect to the mechanical properties, durability and thermal behavior, ground-granulated blast-furnace slag (GGBS) delineates a rational way to develop sustainable cement and concrete. Apart from environmental benefits, the replacement of cement by GGBS illustrates an adequate way to mitigate the economic impact. Although many researchers concentrate on utilizing GGBS in concrete production, knowledge is scattered, and additional research is needed to better understand relationships among a wide spectrum of key questions and to more accurately determine these preliminary findings. This work aims to shed some light on the scientific literature focusing on the use and effectiveness of GGBS as an alternative to cement. First and foremost, basic information on GGBS manufacturing and its physical, chemical and hydraulic activity and heat of hydration are thoroughly discussed. In a following step, fresh concrete properties, such as flowability and mechanical strength, are examined. Furthermore, the durability of concrete, such as density, permeability, acid resistance, carbonation depth and dry shrinkage, are also reviewed and interpreted. It can be deduced that the chemical structure of GGBS is parallel to that of cement, as it shows the creditability of being partially integrated and overall suggests an alternative to Ordinary Portland Cement (OPC). On the basis of such adjustments, the mechanical strength of concrete with GGBS has shown an increase, to a certain degree; however, the flowability of concrete has been reduced. In addition, the durability of concrete containing GGBS cement is shown to be superior. The optimum percentage of GGBS is an essential aspect of better performance. Previous studies have suggested different optimum percentages of GGBS varying from 10 to 20%, depending on the source of GGBS, concrete mix design and particle size of GGBS. Finally, the review also presents some basic process improvement tips for future generations to use GGBS in concrete