Architectural Engineering Commons^™

Seismic Design Of Timber Panelized Roof Structures, John W. Lawson

Architectural Engineering

No abstract provided.

An Adaptive Utility Interactive Photovoltaic System Based On A Flexible Switch Matrix To Optimize Performance In Real-Time, Mahmoud Alahmad, Mohamed Amer Chaaban, Siu Kit Lau, Jonathan Shi, Jill Neal

Durham School of Architectural Engineering and Construction: Faculty Publications

Reconfigurable architectures are of great interest to system designers to improve the system’s operation and efficiency. In this paper, we propose an adaptive utility interactive photovoltaic (PV) system based on a novel Flexible Switch array Matrix topology. This proposed system maximizes the generated power in real-time in response to operational conditions such as shading, soiling, mismatches, and module failure among others. The proposed system is a compromise in the utilization of power conditioning equipment to maximize energy capture and system efficiency. Simulation results demonstrate an average 13% improvement in efficiency when compared with the central inverter topology performance. A prototype …

Effects Of Roof Pitch On Air Flow And Heating Load Of Sealed And Vented Attics For Gable-Roof Residential Buildings, Shimin Wang, Zhigang Shen

Durham School of Architectural Engineering and Construction: Faculty Publications

Pitch value is an important consideration in residential gable roof design and construction. However, how roof pitch, coupled with air flows in attic space, affects the energy performance of building attics has been barely investigated. In this paper, a 2D unsteady computational fluid dynamics (CFD) model is employed to investigate the effects of roof pitch on air flow and heating load of both sealed and vented attics for gable-roof residential buildings. The simulation results show that air flow in the sealed attics is steady and asymmetric, while that in the vented attics is a combination of an essentially symmetric base …

Wind Design Of Timber Panelized Roof Structures, Brian Vandenburgh, John W. Lawson

Architectural Engineering

No abstract provided.

Effects Of Inclusion Shapes Within Rigid Porous Materials On Acoustic Performance, Hyun Hong, Siu-Kit Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

The present study investigates the influence of various shapes of inclusions having same volume embedded in a porous rigid material. Previous studies showed improvement of the broadband sound absorption with particular shapes of inclusions. However, different volumes of the inclusions have been considered; therefore, the bulk densities are not the same for comparison. The present study extends the investigations of inclusions in porous materials with same volume (or bulk density) to eliminate the influence by the change of bulk density. The effects of shape will be discussed. Finite element modeling will be used for this study. Total four different shapes: …

Impacts Of Ventilation Ratio And Vent Balance On Cooling Load And Air Flow Of Naturally Ventilated Attics, Shimin Wang, Zhigang Shen

Durham School of Architectural Engineering and Construction: Faculty Publications

The impacts of ventilation ratio and vent balance on cooling load and air flow of naturally ventilated attics are studied in this paper using an unsteady computational fluid dynamics (CFD) model. Buoyancy-driven turbulent ventilations in attics of gable-roof residential buildings are simulated for typical summer conditions. Ventilation ratios from 1/400 to 1/25 combined with both balanced and unbalanced vent configurations are investigated. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively insensitive to the variations in ventilation ratio and vent configuration. The predicted temperature fields are characterized …

The Impact Of Roof Pitch And Ceiling Insulation On Cooling Load Of Naturally-Ventilated Attics, Shimin Wang, Zhigang Shen, Linxia Gu

Durham School of Architectural Engineering and Construction: Faculty Publications

A 2D unsteady computational fluid dynamics (CFD) model is employed to simulate buoyancy-driven turbulent ventilation in attics with different pitch values and ceiling insulation levels under summer conditions. The impacts of roof pitch and ceiling insulation on the cooling load of gable-roof residential buildings are investigated based on the simulation of turbulent air flow and natural convection heat transfer in attic spaces with roof pitches from 3/12 to 18/12 combined with ceiling insulation levels from R-1.2 to R-40. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively …

Development And Evaluation Of A Simplified Modeling Approach For Hydraulic Systems, Yuebin Yu, Vivian Loftness, Daihong Yu, Yan Lu, Volker Hartkopf

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents how a hydraulic system can be properly modeled for hydraulic balancing, knowledge of flow distribution, coupled simulation, and evaluation of control, etc. It focuses on water-based heating and cooling systems, which generally have high energy efficiency in design but could perform poorly in reality due to the undersensing condition and strong thermal-hydraulic coupling. The study introduces the motivation, presents the simplified modeling methodology, and illustrates the model and simulating structure. A preliminary evaluation of the method is conducted with two simple simulations. The proposed “node-branch-state” modeling approach could be easily modified, expanded and integrated into a detailed …

Numerical Simulation Of Centrifuge Tests On Homogeneous And Heterogeneous Soil Models, Pradipta Chakrabortty, Radu Popescu

Architectural Engineering

Soil liquefaction is a major cause of seismic damage in cohessionless soil during earthquakes. From past numerical and experimental research it has been observed that more excess pore water pressure (EPWP) is generated during earthquakes in a heterogeneous soil deposit than in the corresponding homogeneous soil with relative density equal to the average relative density of the heterogeneous soil. This interesting phenomenon is investigated here, by numerically simulating centrifuge experiments of seismically induced soil liquefaction using the finite element code DYNAFLOW. Two centrifuge tests are numerically simulated here: one in homogeneous soil and another in heterogeneous soil. Recorded experimental results …

Ann Based Load Identification And Forecasting System For The Built Environment, Hosen Hasna

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

"Phantom Loads" cause energy waste in homes and the built environment as a whole. Consumers spend more than $3 billion a year on "Phantom Load" in the United States alone. The goal of this work is to conserve energy by increasing consumer awareness on their energy usage and appropriate tools which in turn will be reducing and /or eliminating phantom loads and mismanagement of the load in the built environment. A further goal is to improve upon existing power distribution systems in the built environment with limited hardware additions to increase energy conservation. This work investigates remote identification of load …

Modeling Unbound Granular Materials Under Complex Stress Paths, Cheng Chen, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Developing reliable and versatile constitutive models for geomaterials has been challenging tasks for nonlinear finite element analysis of geotechnical engineering systems. the fuzzy set plasticity theory has been developed to account for the nonlinear soil stress-strain response under complex stress paths. the theory in many ways resembles the bounding surface plasticity, where the plastic modulus is a function of the distance between the current and image stress states in the stress space. based on the concept of fuzzy set theory in mathematics, a membership function whose value ranges from 1 and 0 is introduced in the Fuzzy Set Plasticity Theory …

Characterization Of Crushed Rock-Concrete Interface Behavior Through The Parallel Gradation Technique, Domenica Cambio, Xin Kang, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The response of a soil-structure system subjected to monotonic or cyclic loading is influenced significantly by the mechanical behavior of soil-structure interface. in this paper, the friction characteristics of the crushed rock-concrete interface and the role of the crushed rock deformability were examined through a series of monotonic and cyclic direct shear tests. the physical modeling technique of parallel gradation was adopted where two parallel gradation curves of the crushed rocks were prepared and used in the tests. the tests were carried out in dry condition and with two initial void ratios representing both loose and dense states. Two concrete …

Measuring Global Response Of A Wind Turbine To Simulated Earthquake Shaking Assisted By Point Tracking Videogrammetry, Ian Prowell, Tim Schmidt, Ahmed Elgamal, Chia Ming Uang, Hal Romanowitz, J. Edward Duggan

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Experiments investigating earthquake response of structures traditionally use conventional wired instruments such as strain gauges, displacement transducers, and accelerometers deployed at key areas of interest throughout structure. for wind turbines the rotor is one of these key areas, but due to rotation it is not possible to use wired instruments without a special slip ring. in a recent experiment conducted using the Network for Earthquake Engineering Simulation (NEES) Large High Performance Shake Table (LHPOST) at the University of California, San Diego (UCSD) the global response of a full scale 65-kW turbine (22 m hub height) was monitored using a novel …

Application Of Threshold Concepts To Improve A Design-Focused Course In Transportation Engineering, Dan Cernusca, Ghulam Bham

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Design is an integral part of engineering courses. to address its associated problems, however, is a challenging task in instruction because of design's open-endedness and complexity. in this study, two theoretical models were implemented in an introductory transportation engineering course to address the challenges associated with design of a highway. First, the theoretical framework proposed by the threshold concepts model was used to identify a candidate concept for the instructional redesign process. Two major characteristics of threshold concepts, integrativity and transformativity, were used to identify horizontal alignment as a candidate concept for the highway design process. Second, concept mapping was …

Evaluation Of Pre-Consolidation Stress Determination Methods, Omar Conte, Stephanie Rust, Louis Ge, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Pre-Consolidation Pressure Provides Valuable Information About Soil Behavior And, Specifically, Settlement under an Induced Load. Soil is Expected to Have Less Settlement Before its Pre-Consolidation Pressure and Much More Settlement after that Point. the Pre-Consolidation Pressure and the Compressibility of the Soil Can Be Determined from the Results of a One-Dimensional Consolidation Test. Different Methods Have Been Developed to Obtain the Accurate Pre-Consolidation Pressure from One Dimensional Consolidation Test Data. This Paper Presents and Discusses the Results of the One-Dimensional Consolidation Test Data from an Extensive Testing Program. the Test Specimens Used Were Obtained from Multiple Borehole Locations and Were …

Life Cycle Costing Template (Excel), Dermot Kehily

Reports

No abstract provided.

Technologies Enabling Sustainability In The Built Environment, Mahmoud Alahmad, Muhammad Zulfiqar, Hosen Hasna Hh, Timothy Wisnieski, Nasser Aljuhaishi, Hamid Sharif

Durham School of Architectural Engineering and Construction: Faculty Publications

Energy conservation is among society’s greatest challenges, and the built environment has a concentrated impact on our natural environment, economy, and health. Fundamental understandings of how energy is consumed, monitored, and controlled are key prerequisites for an energy conservation process. This paper evaluates the effectiveness of real-time energy monitors (RTM) to influence behavior change in residential consumers. A methodology for remote identification of load types along the electrical circuitry where they (load) are being consumed is also presented. The load type and status (on, off, standby) are determined both remotely and in a non-intrusive manner using Non-Intrusive Load Monitoring Methods. …

Fenestration Studies On Building Energy Using The Facade Evaluation Facility, Wendell Cocina

UNLV Theses, Dissertations, Professional Papers, and Capstones

The project was developed to assess several types of facades and their influence on building energy, mainly focused on windows and other building fenestrations. Requirements for the facility are stated in this paper alongside corresponding solutions. The facility is designed to represent a section of a building façade. Experimenting on a wide range of fenestrations including windows with integrated PV elements was the primary prerequisite. The option of removable façade configurations was used and allowed testing specimens to be changed effortlessly. Instrumentation and data acquisition are discussed including calibration and uncertainty analysis. Investigation of the air conditioning unit was concluded …

Developing Dendrifrom Facades Using Flow Nets As A Design Aid, Jonas H. Houston

Master's Theses

This thesis highlights a method of arriving at form that minimizes the need for high end technology and complex mathematical models, yet has structural principles of load flow at the highlighted methods core. Similar to how graphical statics assisted earlier architects and engineers to arrive at form by relating form and forces, this thesis suggests a method of form finding that relates the flow of stresses within solid masses to possible load-bearing façades. Looking to nature, where an abundance of efficient structural solutions can be found, this thesis focuses on a tree-like structural form called the dendriform. In doing so, …

Verification And Expansion Of Single-Degree-Of-Freedom Transformation Factors For Beams Using A Multi-Degree-Of-Freedom Non-Linear Numerical Analysis Method, Takayuki Yokoyama

Master's Theses

The single-degree-of-freedom (SDOF) transformation factors as tabulated in John Biggs’ textbook (Biggs 1964) are accepted as the equivalent factors for simplifying and analyzing a component's response to blast. The study validates the stiffness and mass transformation factors through multi-degree-of-freedom (MDOF) numerical methods. After validating the transformation factors, the MDOF numerical method is used to create new stiffness and mass transformation factors for loading cases not already included in Biggs’ textbook.

The validated factors, as well as the newly developed factors are used in SDOF analyses. The deflections from the SDOF responses accurately predict the MDOF responses as long as the …