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Architectural Engineering Commons™

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2010

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Articles 61 - 72 of 72

Full-Text Articles in Architectural Engineering

High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 1: Prestress Loss And Camber Behavior, Jared E. Brewe, John J. Myers Jan 2010

High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 1: Prestress Loss And Camber Behavior, Jared E. Brewe, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The design of prestressed concrete members is restricted by the requirement that the extreme compressive fiber stress at midspan of simply supported members be less than 60% of the concrete compressive strength at release of prestressing. the purported purpose of this limit is to address serviceability performance, but it places unnecessary limits on the capability of the materials. for this research program, six prestressed concrete girders were produced with high-strength self-consolidating concrete and subjected to compressive fiber stress levels ranging from 65% to 84% of the concrete compressive strength at release of prestressing. Time dependent concrete surface strains were measured …

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Active Noise Barrier Minimizing Pressure Gradient, Carl Hart, Siu-Kit Lau Jan 2010

Active Noise Barrier Minimizing Pressure Gradient, Carl Hart, Siu-Kit Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

Minimization of the sound pressure field within the shadow zone of a noise barrier is achieved by reducing the pressure gradient along a line, at the top of a barrier, via active noise control. The noise control effectiveness of a barrier is increased by this strategy, especially for specific system configurations. The proposed method was evaluated by numerical simulation. Results indicate that system orientation has little effect on minimizing the pressure gradient at the top of the barrier when the error sensors are invisible to the primary noise disturbance. Highly effective control within the shadow zone and close to the …

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Concrete Slender Wall Design – Back To The Future, John W. Lawson, James Lai Jan 2010

Concrete Slender Wall Design – Back To The Future, John W. Lawson, James Lai

Architectural Engineering

Slender concrete walls incorporated into tilt-up construction
over the past 60 years have performed remarkably well under
out-of-plane wind and seismic loads. While issues associated
with seismic wall anchorage gave this form of construction a
black-eye in the early days, the concrete walls themselves
have always performed very well even as far back as their
first use in the early 1900s. Yet the height-to-thickness
limitations in 1985 and earlier model building codes were
proved irrational and were removed. We as engineers expect
building codes to evolve and advance the state of the art with
each successive edition. The latest edition …

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Guide To Stones Used For Houses Of Worship In Northeastern Ohio, Joseph T. Hannibal Jan 2010

Guide To Stones Used For Houses Of Worship In Northeastern Ohio, Joseph T. Hannibal

Cleveland Memory

The purpose of this guide is to serve as an introduction and field guide to the stone used for Northeastern Ohio’s sacred landmarks. compiling this information are noted. Both exterior and interior stones are described. Locations are given so that visitors can find various interior features. Finally, interesting facts having to do with the stones are given in a remarks section and references to sources used. Original publication date 1999.

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Ab-10-C037: Effects Of Noise From Building Mechanical Systems On Elementary School Student Achievement, Lauren M. Ronsse, Lily M. Wang Jan 2010

Ab-10-C037: Effects Of Noise From Building Mechanical Systems On Elementary School Student Achievement, Lauren M. Ronsse, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This project seeks to determine what relationship, if any, exists betweenbackground noise levels in elementary classrooms due to the building mechanicalsystems and student performance on achievement tests. Previous research inclassroom acoustics has clearly identified that lower background noise levelsresult in higher speech intelligibility which is crucial for the learning process;however, there is a lack of data correlating lower noise levels to improved studentachievement scores. For this study, background noise level measurements were madein 14 elementary schools in a public school system in Council Bluffs, Iowa, USA.The measurements were made in unoccupied classrooms with the central buildingmechanical systems activated. Second and …

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Optimum Absorption And Aperture Parameters For Realistic Coupled Volume Spaces Determined From Computational Analysis And Subjective Testing Results, David T. Bradley, Lily M. Wang Jan 2010

Optimum Absorption And Aperture Parameters For Realistic Coupled Volume Spaces Determined From Computational Analysis And Subjective Testing Results, David T. Bradley, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This project utilizes computational modeling to study the effects of varying two architectural parameters, absorption ratio and aperture size, in a realistic coupled volume concert hall. Coupled volumes have been shown to exhibit non-exponential sound energy decay profiles, referred to as double slope effect. A number of objective metrics (T30/T15, LDT/T10, decay ratio, and ΔL) have been used to quantify the double slope effect of the profiles generated in the virtual hall. T30/T15 and LDT/T10 showed similar trends across all hall configurations, indicating decreasing double slope effect with increasing coupled volume absorption ratio for each aperture size, and producing highest …

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Ab-10-018: The Effects Of Noise From Building Mechanical Systems With Tonal Components On Human Performance And Perception (1322-Rp), Erica E. Ryherd, Lily M. Wang Jan 2010

Ab-10-018: The Effects Of Noise From Building Mechanical Systems With Tonal Components On Human Performance And Perception (1322-Rp), Erica E. Ryherd, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This study investigated the effects of noise from building mechanical systems with tonal components on human task performance and perception. Six different noise conditions based on in-situ measurements were reproduced in an office-like setting; all were set to approximately the same sound level (47 dBA) but could have one particular tonal frequency (120 Hz, 235 Hz, or 595 Hz) at one of two tonal prominence ratios (5 or 9). Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately 1 hour to each noise condition. Results show that the noise …

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Computational Modeling Of Effects Of Alloying Elements On Elastic Coefficients, Z. K. Liu, H. Zhang, S. Ganeshan, Y. Wang, S. N. Mathaudhu Jan 2010

Computational Modeling Of Effects Of Alloying Elements On Elastic Coefficients, Z. K. Liu, H. Zhang, S. Ganeshan, Y. Wang, S. N. Mathaudhu

Durham School of Architectural Engineering and Construction: Faculty Publications

Models for composition and temperature dependencies of single-crystal elastic stiffness coefficients are developed and applied to the Al12Mg17 and hexagonal closed-packed solution phases in the Mg–Al system based on data from first-principles calculations. In combination with models for multi-phases, the bulk, shear, and Young’s moduli of Mg–Al alloys are predicted and compared with available experimental data in the literature. It is noted that both phase transition and grain boundary sliding may play important roles in the elastic coefficients as a function of temperature.

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Ab-10-017: Combined Effects Of Noise And Temperature On Human Comfort And Performance (1128-Rp), Dale Tiller, Lily M. Wang, Amy Musser, Matthew Radik Jan 2010

Ab-10-017: Combined Effects Of Noise And Temperature On Human Comfort And Performance (1128-Rp), Dale Tiller, Lily M. Wang, Amy Musser, Matthew Radik

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper summarizes results from an experiment designed to investigate the combined effects of noise and temperature on human thermal comfort and task performance. Thirty subjects (16 females, 14 males) were exposed to all combinations of five thermal conditions (PMV +1 [79.6°F:26.4°C], PMV +0.5 [75.8°F:24.3°C], PMV 0 [72.1°F:22.3°C], PMV -0.5 [68.3°F:20.2°C], and PMV -1 [64.6°F:18.1°C]), three RC noise levels (RC-30, RC-40, and RC-50), and two sound qualities (neutral and rumbly): all sounds mimicked noise from building ventilation systems. After a one-hour adaptation period at each condition, subjects rated their thermal comfort using the ASHRAE Thermal Comfort Scale and the Tenant …

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Ab-10-019: Human Performance And Perception-Based Evaluations Of Indoor Noise Criteria For Rating Mechanical System Noise With Time-Varying Fluctuations (1322-Rp), Lily M. Wang, Cathleen C. Novak Jan 2010

Ab-10-019: Human Performance And Perception-Based Evaluations Of Indoor Noise Criteria For Rating Mechanical System Noise With Time-Varying Fluctuations (1322-Rp), Lily M. Wang, Cathleen C. Novak

Durham School of Architectural Engineering and Construction: Faculty Publications

The goal of this study was to investigate the effects of noise from building mechanical systems with time-varying fluctuations on human task performance and perception, and to determine how well current indoor noise rating methods account for this performance and perception. Six different noise conditions with varying degrees of time-varying fluctuations, many focused in the low frequency rumble region, were reproduced in an office-like setting. Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately one hour to each noise condition. Results show that the noise conditions with higher sound …

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Feasibility Study Of Solar Driven Underground Cooling System, Michel E. Shafik Jan 2010

Feasibility Study Of Solar Driven Underground Cooling System, Michel E. Shafik

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

In the United States the peak electrical use occurs during the summer. In addition, the building sector consumes a major portion of the annual electrical energy consumption. One of the main energy consuming components in the building sector is the Heating, Ventilation, and Air-Conditioning (HVAC) systems. This research studies the feasibility of implementing a solar driven underground cooling system that could contribute to reducing building cooling loads. The developed system consists of an Earth-to-Air Heat Exchanger (EAHE) coupled with a solar chimney that provides a natural cool draft to the test facility building at the Solar Energy Research Test Facility …

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Noise Propagation Through Open Windows Of Finite Depth Into An Enclosure, Caleb Sieck, Siu-Kit Lau Jan 2010

Noise Propagation Through Open Windows Of Finite Depth Into An Enclosure, Caleb Sieck, Siu-Kit Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

Predicting the insertion loss of an opening backed with an enclosed space is important for building noise control. Recent research in sound transmission through apertures of finite depth in infinite rigid baffles has included the effects of propagating and evanescent modes within the aperture in order to extend models to higher frequencies. The present study extends the model to the case of the aperture backed by a cavity as opposed to sound radiating into half-space. The role of coupling between the aperture modes, radiation modes, and cavity modes in the transmission was investigated. The results were compared to those of …

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