Advances in Civil and Architectural Engineering

Cotton knitted fabric waste as reinforcement in cement screed

2023-12-05T08:41:03+01:00

Cement screed consists of cement, sharp sand and water, laid as a thin layer over the concrete subfloor. Although the screed is strong, it can be additionally reinforced with fibres, most often polypropylene fibres. In this study, cotton knitted fabric waste (CKFW) was obtained from a local factory producing underwear to reinforce the cement screed. A total of eight mixtures were made: reference mixture, screed reinforced with polypropylene fibres and six mixtures reinforced with CKFW. CKFW was added in 1,25 %, 2,50 % and 5,00 % of the total volume. Before adding to the mixtures, the first CKFW group was saturated with tap water, whereas, the second CKFW group was saturated with dispersion that improves adhesion. The density and air content of the fresh mixtures were tested, and the compressive strength and flexural strength were determined when the specimens were 28 days old. The specific fracture energy is determined based on the curve from the plot of load vs. displacement. The CKFW increases the ductility of cement screeds, although it has no significant effect on the compressive and flexural strength of the specimens. The CKFW that was saturated with tap water achieved better results.

Fundamental period equations for plan irregular moment-resisting frame buildings

2023-11-03T08:06:48+01:00

The fundamental natural period of oscillation is a critical parameter in evaluating the design base shear of buildings. Worldwide seismic design codes typically employ height-based empirical formulas to estimate this period for various building categories, without distinguishing between regular and irregular buildings. This study proposes a formula specifically for reinforced concrete (RC) moment-resisting frame (MRF) buildings with dominant re-entrant corner type plan irregularity. A total of 190 re-entrant corner dominant building models with different shapes (C-, L-, T-, and PLUS-type), heights, and floor configurations were prepared, and eigenvalue analysis (EVA) was conducted. The fundamental natural period of oscillation for each model was evaluated and compared with the height-based formulas from seismic design codes and the period–height relationship proposed in existing literature. A nonlinear regression model, using a multi-variable power function, is proposed to estimate the fundamental natural period for these re-entrant corner dominant building models. This model considers the A/L ratio in both directions of the building, along with its height. Both unconstrained and constrained regression analyses were performed to derive a formula that best fits the fundamental natural period data. The study recommends that the unconstrained best-fit minus one standard deviation curve can conservatively define the fundamental natural period of oscillation for re-entrant corner dominant RC building models. The equation defining this curve has the potential to replace the existing seismic design code-based period-height formula.

Comparative probability-based seismic safety assessment of base-isolated buildings: A case study

2023-12-07T13:18:33+01:00

Seismic fragility curves are used to assess the structural vulnerability probability at various damage states. In this study, the effects of different isolation systems on the seismic safety of a two-dimensional reinforced concrete moment-resisting frame are investigated. The reference structure was a hotel building in California, USA. A comparative probability-based seismic safety assessment for building components was conducted on the superstructure hypothetically fitted with various isolation systems. In this regard, two categories of isolation systems, including rubber‐ and friction‐based systems, were selected. The high damping rubber bearings and friction pendulum systems were considered. Incremental dynamic analyses were conducted for a suite of earthquake records to develop the fragility curves considering modelling, demand, and capacity uncertainties. Based on the results, it was observed that the building failure probability reduction was influenced by the seismic isolation systems rather than the fixed base (un-retrofitted) model. Furthermore, the high damping rubber bearings system was found to be more reliable than the friction pendulum system in the limit states considered. However, no significant discrepancy was observed in the performance of the building fitted with isolation systems at higher damage states.

Preliminary small-scaled thermal resistance testing of a masonry wall with enhanced electromagnetic shielding effectiveness

2024-01-08T11:13:05+01:00

This study presents the preliminary results of a small-scale masonry wall thermal resistance (R-value) measurement. Two small-scale masonry walls were constructed using regular and antimony tin oxide (ATO)-containing bricks. ATO has shown potential for improving the protection against electromagnetic radiation penetration. R-values of the walls were measured using a FluxDAQ device equipped with a heat flux sensor and two temperature sensors for obtaining the heat flux and inside and outside temperatures during the measurement. Furthermore, the thermal conductivity (λ) of the bricks was measured by using the Fox200 Heat Flow Meter. Both results can be used for determining a walls’ thermal transmittance (U-value), which is often used for describing the energy losses and as a measure of a wall's energy efficiency. This research sought to investigate whether there is a correlation between the results obtained by the small-scale masonry wall and Fox200 device. Ultimately, this experiment aims to verify whether the small-scale masonry wall non-standard method described herein can provide approximately similar results to the standardised method.

Role of spatial efficiency, layout planning, and sustainability in the success of shopping malls

2023-09-26T11:27:59+02:00

Building multi-storey shopping malls has grown to be a very lucrative industry for investors in recent years. As a result, the success of a plaza depends on a variety of elements, including its design, security, appealing façade, and amenities. This study examined the structural systems, services, and architectural designs of a few of Lahore's prosperous plazas. Food courts and hyper malls provide essential functions that boost foot traffic and have the potential to revolutionise the way that entertainment amenities raise a mall's worth. Mixed-use multi-story spaces such as those that combine offices, apartments, and retail stores can also increase the efficiency of a mall in terms of sales and attractiveness. The assessment parameters in case studies include the gross area, circulation, parking area, toilet area, services area, and vertical transportation, with average values of 33,83 %, 22,00 %, 24,30 %,1,10 %, 3,05 %, and 4,60 %, respectively. These will assist future studies to determine the minimum threshold for success, making mall planning easier and more accurate. High-quality malls have higher occupancy because they offer better quality development, facilities, sustainable techniques, and amenities to support the overall development, along with shop sizes that suit international brands. This research defines the emerging trends and provides guidelines for the future architectural planning, structural systems, and services of shopping malls in Lahore to meet sustainable development goals and attract more shoppers.

Effect of single vanes on turbulent flow

2024-01-15T12:08:36+01:00

In response to growing environmental and ecological awareness, eco-friendly in-stream structures such as vanes have been implemented in different parts of the world to enhance stream conditions. FLUENT (ANSYS) was used to perform three-dimensional large eddy simulation to investigate the effect of the vanes permeability rate on flow characteristics. To evaluate the numerical model accuracy, numerical and experimental free surface profiles compared. It is observed that simulated free surface profiles agree reasonably well with measured values. The effect of different permeability rates is obvious in the flow characteristics such as depth-averaged velocity distribution, tip velocity variations, formation of the secondary flows in the flow field, turbulent kinetic energy, and mean kinetic energy contours. On average, maximum velocity values in the flow field is 1,54 times the approach velocity. Tip velocity decreases up to 30,6 % for the 70,0 % permeable vane. Maximum turbulent kinetic energy and mean kinetic energy for the 70,0 % permeable vane decrease up to 58,0 % and 43,3 %, respectively. Generally significant velocity and flow pattern variations around the impermeable vane can be attributed to the local effect of the vane structure and channel cross sectional constriction in comparison to the permeable vanes.

Sustainable energy production and resilience towards floods by using hydro and solar photovoltaic energy

2024-01-22T11:44:02+01:00

Unexpected and intense floods have become more frequent recently; this is related to extreme weather events that are difficult to predict accurately. This necessitates new solutions to decrease the risk of flooding urban and rural areas. Moreover, such solutions should have negligible impact on the environment. There are several concepts, tools, and technical measures for preventing floods, one of which is the ‘monkey cheek’ concept for flood protection, used in Thailand for protection from river and sea floods. Monkeys collect food in their mouths and eat subsequently in stages. In a similar manner, excess water from floods could be collected and stored in reservoirs, sags, canals, floodplain forests, and unused space. Collected water could then be used for irrigation. In most cases, collected water must be pumped to distant or higher locations compared to the location where the water was collected. This requires electric energy for the pumps. This paper analyses a case study for the presented concept for the town of Ludbreg in Croatia, currently undergoing real-site measurements and calculations. A rescaled adjusted partial sums method is applied for the analysis. It has been shown that the energy potential of the local, small river Bednja in the observed location could be approximated using the “monkey cheek’’ concept. Within this, using the produced electricity from small hydropower plants and solar photovoltaic systems has been proven promising. The solution avoids building dams for flood protection, satisfying the environmental aspects.

Recycled concrete aggregate and cinder gravel as base course construction materials

2024-02-10T18:52:56+01:00

In this research, the potential use of recycled concrete aggregate (RCA) and CG as a base course construction material was investigated. A laboratory test involving the mechanical stabilization of RCA and CG was conducted to examine their physical properties. Eight samples of RCA blended with CG in varying proportions from 0% to 100 % with 10 % variation were studied. The laboratory test results indicate that 100 % CG yields specific gravity (SG), aggregate crushing value (ACV), aggregate impact value (AIV), Los Angeles abrasion (LAA), flakiness index (FI), elongation index (EI), plasticity index (PI), water absorption, soundness, and California bearing ratio (CBR) values of 2,54 %, 38,37 %, 20,10 %, 33,17 %, 5,59 %, 12,09 %, 0,90 %, 3,52 %, 10,60 %, and 38,08 %, respectively. The results for 100% RCA show SG, ACV, AIV, LAA, FI, EI, PI, water absorption, soundness, and CBR values of 2,70 %, 9,56 %, 5,30 %, 9,20 %, 15,30 %, 15,84 %, NP, 0,23 %, 1,49 %, and 105,87 %, respectively. These results also fail to meet the gradation requirements based on ERA standard specifications. Therefore, mechanical stabilization was adopted to improve the physical properties of the samples. Blending 60 % RCA with 40 % CG resulted in SG, ACV, AIV, LAA, FI, EI, PI, water absorption, soundness, and CBR values of 2,65 %, 19,46 %, 10,70 %, 10,88 %, 16,15 %, 22,01 %, NP, 0,26 %, 2,09 %, and 101,98 %, respectively. At this proportion, the gradation aligns with the required ERA standard specifications for GB2 and GB3 materials. Therefore, CG up to 40 % by weight with 60 % RCA is viable for road base course construction, especially when readily available or nearby.

Soft computing techniques for analysing the mechanical properties of egg shell powder-based concrete

2024-03-18T08:33:49+01:00

The construction industry is increasingly focused on sustainability to reduce environmental impact. Researchers are actively exploring alternative materials to replace clinker-based binders. This study specifically investigates the use of eggshell powder (ESP) as a sustainable substitute in construction. Portland slag cement (PSC) is partially replaced by ESP in concrete production for this purpose. To assess the effectiveness of ESP in enhancing binder properties, the study analyses experimental data for compressive and flexural strength. Artificial Neural Network (ANN) modelling is employed for this analysis to predict material performance. The model undergoes training and testing using input data to ensure accuracy and reliability. The success of the study is demonstrated by high R2 values, with 0,9915 for compressive strength and 0,9921 for flexural strength, indicating that the ANN model closely matches actual material performance. Additionally, error analysis confirms the model's remarkable accuracy in predicting real-world results. Furthermore, the research highlights the exceptional potential of the developed ANN model, which can effectively predict the mechanical properties of construction materials containing ESP.

Assessment of the discrepancy between daylight factor and using illuminance data methods by climate zones under EN:17037

2024-02-19T10:30:10+01:00

Conducting a rigorous evaluation of the daylight performance of buildings is essential for human health and energy efficiency. Today, there are two main methods used for analysis: the daylight factor, which has been used since the early 1900s, and the newer approach known as climate-based modelling. Both methods are employed in the EN 17037 Daylight in Buildings’ standard. Utilizing different calculation methods causes discrepancies in daylight provision performance analyses of a room. However, there is no definition or limitation for this subject in the standard. As a result, researchers prefer different calculation methods for the same location in daylighting analyses without a clear justification. Additionally, there is a lack of parametric methods that follow the guidelines of the standard. This study aims to analyse the impact of calculation methods on daylighting analyses according to different regions and generate parametric methods in compliance with the standard. In this respect, comparison calculations are conducted for a theoretical room situated in all 81 provinces of Turkey, where variant climate types occur over a year. Furthermore, parametric workflows are generated using Rhinoceros/Grasshopper following the directives of the standard. The findings indicate that the method choice affects the illumination levels in all zones, ranging from 15 to 114 %.

Development of a novel sustainable concrete from waste coconut shell with alccofine supplements

2024-01-22T12:53:19+01:00

The infrastructure of a country depends significantly on cement concrete as the primary construction material. The aggregate comprises a significant proportion of the overall volume of concrete. However, the ongoing extraction of granite rock to obtain coarse aggregate contributes to the escalating need for natural resources among future generations. Due to its high carbon dioxide (CO2) footprint, the cement industry is a significant contributor to global warming. An appropriate reduction in the amount of cement in concrete without affecting its key properties can result in economical and sustainable development of the construction industry. In this investigation, agricultural waste coconut shell is considered as a substitute for conventional aggregate in concrete to produce lightweight coconut shell concrete. The alccofine-1203 contains ultrafine particles with a distinctive composition that enhances the pozzolanic and hydration process in concrete. Alccofine ranging from 5 % to 15 % were added to cement. The results demonstrated that the 10 % alccofine enhanced the fresh and mechanical properties of the lightweight coconut shell concrete. Using a combination of coconut shell and alccofine in concrete would be the most environmentally sustainable option in the construction industry.

A review of the relationships between safety risk factors, practical solutions, and sustainable construction

2024-01-08T10:40:10+01:00

Sustainability encompasses environmental, economic, and social dimensions, with safety standing as a crucial facet within the construction industry's social sustainability framework. This study addresses this vital concern by comprehensively analyzing published research on prominent safety risk factors and effective mitigation measures in construction projects, considering their influence on the industry's sustainability. A systematic literature review spanning 2008 to 2023 examined 32 pertinent articles from reputable journals. The review revealed 25 identified safety risk factors and 20 corresponding effective measures. These were categorised into labour, environmental, technical, and financial risks, forming the basis for a network diagram illustrating their interrelationships and associated mitigation strategies. Moreover, the study introduced a sustainability criterion, evaluating the various safety risk factor categories, and highlighting labour and environmental risks as the most significant concerns among the factors assessed. Finally, the research proposes future research directions aimed at elevating safety and sustainability within construction projects.