Architecture Commons^™

Reducing Early-Age Shrinkage Cracks Of Bridge Decks And Rails, Soumitra Das, George Morcous, Jiong Hu

UNL Student Research Days Posters, Graduate

Early-age shrinkage cracking of concrete bridge decks and rails accelerates the penetration of water and chemicals which leads to reinforcement corrosion, delamination, and eventually spalling. All this results in shorter service life, road closure, and costly repair. Development of Low-cement concrete(LCC) mix to reduce early age shrinkage crack through aggregate grading optimization was done in this research work. This approach also reduces concrete cost ($15-$20/cyd) (15–25%) and its carbon footprint (≈15%).

Facilitating The Industrial Sector's Adoption Of Collaborative Project Delivery Methods, Xavier Wood-Aliberch

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

In an effort to improve outcomes in the civil and healthcare sectors, clients have adopted collaborative project delivery methods for the delivery of their capital projects. The success stories in these sectors have gathered the attention of clients in the industrial sector, where cost and schedule overruns have become the norm. The central objective of this thesis is to help clients make the transition to this new type of project delivery.

This thesis was written in a three-paper format, where each paper addresses a challenge with the adoption of collaborative delivery methods. The first paper investigates what type of industrial …

Evaluation Of The Dynamic Behavior Of Steel Staircases With Concrete Filled Pan Treads, Tyler Sondag

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

Vibration serviceability of staircases has been a growing challenge for structural engineers due to changing materials and structural forms. In order to prevent or correct serviceability problems due to structural vibrations, structural engineers should be able to predict the dynamic performance of a staircase structure. However, there are few technical guides available for designing steel staircases, and the ones that do exist are often limited in their applications. Currently, there is a lack of research on staircases that are less prone to vibrations, such as staircases with concrete filled pans that are composed of face and wall stringers. Therefore, the …

Case Study Of Quantifying Energy Loss Through Ceiling-Attic Recessed Lighting Fixtures Through 3d Numerical Simulation, Ri Na, Shengmao Lin, Zhigang Shen, Linxia Gu

Durham School of Architectural Engineering and Construction: Faculty Publications

Air leakage through improperly installed recessed lighting fixtures has been identified as a common issue causing extra energy consumption of residential buildings. However, little quantitative study was found in this area. In this paper, a preliminary evaluation of the magnitude of such energy loss was conducted by numerical simulations using 3 dimensional transient computational fluid dynamics (CFD) model. A typical layout of recessed lighting fixtures was used in this case study with boundary conditions in four different seasons, which were obtained from past measured roof/attic temperature data sets. The results of the numerical simulations indicate that leakage of recessed lighting …

Subjective Perception Of Varying Reflection Densities In Room Impulse Responses, Hyun Hong

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

Reverberation time (RT) is a metric commonly used to describe room acoustic conditions, but different rooms which have the same reverberation time can have different reflection densities. Much less is known about how humans perceive different reflection densities and how sensitive humans are to changes in reflection density. Previous investigations in the existing literature have studied the upper limit of distinguishable reflection density using artificial impulse responses, but not with more realistic impulse responses simulated in room acoustic software or measured from real rooms. The aim of this dissertation is to investigate methods for quantifying reflection density from measured impulse …

Assessing Gait And Postural Stability Of Construction Workers Using Wearable Wireless Sensor Networks, Houtan Jebelli

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Falling accidents are a leading cause of fatal and nonfatal injuries in the construction industry. This fact demonstrates the need for a comprehensive fall-risk analysis that incorporates the effects of construction workers’ physiological characteristics. In this context, the objective of the thesis is to investigate and validate the usefulness of the gait- and postural-stability metrics in assessing construction workers’ fall risks. Diverse metrics that assess the capability to keep the body balanced and maintain coordination of body segments during locomotion (gait stability) and stationary postures (postural stability) have been introduced and used in clinical applications. However, their usefulness in the …

Pump Controller Design For Variable Primary Flow Configuration Systems, Yifan Shi

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

Pump systems are utilized widely in Heating, Ventilation and Air-Conditioning (HVAC) systems. There are mainly three configuration types: (1) the constant primary-only flow configuration, (2) the constant primary/variable secondary flow configuration, and (3) the variable primary-only flow configuration. This thesis focuses on finding the optimal control strategy for it and programming a controller for easy in-field usage.

In this thesis, the pump brake horse power (BHP) of the three pump configurations is simulated and compared using varying control methods. The best pump efficiency staging and DP reset control methods are implemented into the pump controller. A one month field experiment …

Precast Concrete Insulated Wall Panel Corbels Without Thermal Bridging, Mohamed Elkady

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

The common practice in corbel design is to block out the insulation in order to provide a solid concrete area at the corbel location. This connection practice results in thermal bridging, which significantly reduces the energy performance of the panel. For example, the PCI Design Handbook indicates that the reduction in thermal resistance caused by a solid part with an area equal to 9% of the total panel surface area is as high as 42%. This paper presents a discussion of a new concept for corbel design of insulated wall panels with the thermal break totally preserved. Two different designs …