Civil Engineering Commons^™

Experimental And Analytical Methodologies For Predicting Peak Loads On Building Envelopes And Roofing Systems, Maryam Asghari Mooneghi

FIU Electronic Theses and Dissertations

The performance of building envelopes and roofing systems significantly depends on accurate knowledge of wind loads and the response of envelope components under realistic wind conditions. Wind tunnel testing is a well-established practice to determine wind loads on structures. For small structures much larger model scales are needed than for large structures, to maintain modeling accuracy and minimize Reynolds number effects. In these circumstances the ability to obtain a large enough turbulence integral scale is usually compromised by the limited dimensions of the wind tunnel meaning that it is not possible to simulate the low frequency end of the turbulence …

Aerodynamic Testing Of Variable Message Signs, Debbie Meyer

FIU Electronic Theses and Dissertations

The increasing nationwide interest in intelligent transportation systems (ITS) and the need for more efficient transportation have led to the expanding use of variable message sign (VMS) technology. VMS panels are substantially heavier than flat panel aluminum signs and have a larger depth (dimension parallel to the direction of traffic). The additional weight and depth can have a significant effect on the aerodynamic forces and inertial loads transmitted to the support structure. The wind induced drag forces and the response of VMS structures is not well understood. Minimum design requirements for VMS structures are contained in the American Association of …

Evaluating The Impact Of Bridge Deck Removal Method On The Performance Of Precast/Prestressed Concrete I-Girders, Shaddi Assad

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

Wide flange precast/prestressed concrete I-girders have been widely used by several State Departments of Transportation (DOTs) in the last two decades. These girders have many advantages over standard AASHTO I-girders. Their wide and thick bottom flange accommodates a large number of prestressing strands and their wide and thin top flange provides a shorter deck span, reduced girder weight, greater stability in construction, and adequate platform for workers. Despite these advantages, the wide and thin top flange might be disadvantageous when it comes to deck removal, as it is more susceptible to damage. Therefore there is a need to investigate the …

Learning From Earthquakes: 2014 Napa Valley Earthquake Reconnaissance Report, Erica Fischer

Lyles School of Civil Engineering Graduate Student Reports

Structural damage was observed during reconnaissance after the 2014 South Napa Earthquake, and included damage to wine storage and fermentation tanks, collapse of wine storage barrel racks, unreinforced masonry building partial or full collapse, and residential building damage. This type of damage is not unique to the South Napa Earthquake, and was observed after other earthquakes such as the 1977 San Juan Earthquake, and the 2010 Maule Earthquake. Previous research and earthquakes have demonstrated the seismic performance of cylindrical fluid-filled tanks is controlled by both the tank and the sloshing motion of the liquid inside. Unlike building structures, steel tanks …

Increased Span Length For The Mgs Long-Span Guardrail System, Nicholas A. Weiland

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Long-span guardrail systems have been recognized as an effective means of shielding low-fill culverts while minimizing construction efforts and limiting culvert damage and repair. The current MGS long-span design provided the capability to span unsupported lengths up to 25 ft (7.6 m) without the use of nested guardrail. The excellent performance of the MGS long-span system in full-scale crash tests suggested that longer span lengths may be possible with the current design.

A detailed analysis of the MGS long-span guardrail system was performed using the finite element software program LS-DYNA^®. It was shown that the MGS long-span design …

Development Of A Precast Concrete Supertile Roofing System For The Mitigation Of Extreme Wind Events, Brandon L. Mintz

FIU Electronic Theses and Dissertations

Residential roofs have traditionally formed the weakest part of the structure. The connections of roofs to the walls has lacked a clear load path with the result that the structure is weak at this point, leading to the compromise of the structure. Indeed roofs have multiple points of failure that lead to the weakness of the residential structure as a whole. Even if structural failure does not occur, compromise the roofing membrane can lead to high repair costs and property loss. The failure lies in the complex forming of the roof components as the roof aesthetics are placed to protect …

Damping Of Seismic Vibrations Of A 3d Asymmetrical Building Model With Multiple Tmd’S, Jean-Paul Pinelli, Kai Chen, Hector Gutierrez, Rasvan Rusovici

Mechanical and Civil Engineering Faculty Publications

In this paper, the authors investigate the control of the seismic response of a three dimensional asymmetrical tier-building model, with a combination of three tuned mass dampers (TMD) located on the upper floor of the building. The 3D frame model represents a 3-story steel building designed for the SAC project in Los Angeles, California. All the dynamic analyses of the 3D structure are performed in ANSYS. The frequencies of the three TMD's and excitations are tuned to the appropriate fundamental frequencies of the model. The optimal number and location of the TMD's on the top floor are investigated, to reduce …

Seismic Response Of A Tall Building To Recorded And Simulated Ground Motions, Nenad Bijelic, Ting Lin, Gregory Deierlein

Civil and Environmental Engineering Faculty Research and Publications

Seismological modeling technologies are advancing to the stage of enabling fundamental simulation of earthquake fault ruptures, which offer new opportunities to simulate extreme ground motions for collapse safety assessment and earthquake scenarios for community resilience studies. With the goal toward establishing the reliability of simulated ground motions for performance-based engineering, this paper examines the response of a 20-story concrete moment frame building analyzed by nonlinear dynamic analysis under corresponding sets of recorded and simulated ground motions. The simulated ground motions were obtained through a larger validation study via the Southern California Earthquake Center (SCEC) Broadband Platform (BBP) that simulates magnitude …

Development Of A Mash Tl-3 Transition Between Guardrail And Portable Concrete Barriers, David A. Gutierrez

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Often, road construction causes the need to create a work zone. In these scenarios, portable concrete barriers (PCBs) are typically installed to shield workers and equipment from errant vehicles as well as prevent motorists from striking other roadside hazards. For an existing W-beam guardrail system installed adjacent to the roadway and near the work zone, guardrail sections are removed in order to place the portable concrete barrier system. The focus of this research study was to develop a proper stiffness transition between W-beam guardrail and portable concrete barrier systems. This research effort was accomplished through development and refinement of design …

Design Considerations For Integral Abutment/ Jointless Bridges In The Usa, Ralph G. Oesterle, Habib Tabatabai

Civil and Environmental Engineering Faculty Articles

This paper summarizes results of a major study on jointless bridges sponsored by the U.S. Federal Highway Administration. This study included extensive laboratory and field experiments as well as detailed analytical studies. A set of design recommendations were provided. Jointless bridges have reduced maintenance, improved riding quality, lower impact loads, reduced snowplow damage, and structural continuity for live load and seismic resistance. However, the thermal movements of the bridge and restraint forces from the abutments and piers must be considered and accommodated. The general design philosophy is to build flexibility into the support structures to the extent feasible while providing …

Comprehending Performance Of Cross-Frames In Skewed Straight Steel I-Girder Bridges, Jawad H. Gull

FIU Electronic Theses and Dissertations

The effects of support in steel bridges can present significant challenges during the construction. The tendency of girders to twist or layovers during the construction can present a particularly challenging problem regarding detailing cross-frames that provide bracing to steel girders. Methods of detailing cross-frames have been investigated in the past to identify some of the issues related to the behavior of straight and skewed steel bridges. However, the absence of a complete and simplified design approach has led to disputes between stakeholders, costly repairs and delays in the construction.

The main objective of this research is to develop a complete …

Making Bridges Outlast Rising Waters, Daniel Cox

TREC Project Briefs

During Hurricanes Ivan in 2004 and Katrina in 2005, at least 11 highway and railroad bridges along the U.S. Gulf Coast were damaged by wave forces. The spans of these bridges typically rested on bent column supports, and were attached to the supports by a variety of connection methods. Failure of these connections caused bridge spans to be washed away when the water rose high enough to lift them off. To build bridges that can withstand such forces, engineers must be able to estimate the effects the forces will have.

Investigator Daniel Cox of Oregon State University has conducted wave …

Testing And Strengthening Bridge Connections, Christopher Higgins, Peter Dusicka, Michael Scott

TREC Project Briefs

Researchers evaluate and improve the strength of gusset plate connections, essential pieces in bridge design that can fail due to buckling.

Numerical Evaluation Of The Extended Endplate Moment Connection Subjected To Cyclic Loading, Mehdi Ghassemieh, Mehdi Jalalpour, Ali Akbar Gholampour

Civil and Environmental Engineering Faculty Publications

In this paper, the seismic behaviour of extended endplate moment connection is analysed using finite element method (FEM). First, an existing test setup is modelled and analysed using ANSYS computer program. The model is validated by comparing the results from the finite element with the experimental ones. Afterwards, by changing the dimensions of members of the connection, their effect on the overall seismic performance of connection is investigated. The results show that by enlarging the column depth and stiffening the connection, the seismic performance is improved and the thickness of endplate should be chosen in a way that its moment …

Mechanical And Transport Properties Of Alkali-Activated Natural Pozzolans As Sustainable Binders, Brittany Radke

Calvert Undergraduate Research Awards

OPC production accounts for 5 to 7% of the global carbon dioxide (CO₂) emissions, contributing to global warming. The desire to reduce CO₂ emissions and produce more durable concrete has given impetus to search for new binders. It is suggested that alkali-activated natural pozzolans have the potential for use as a sustainable replacement for OPC in concrete.

The current study presented herein evaluated fresh, mechanical, and transport properties of alkali-activated natural pozzolan mortars containing various concentrations of sodium hydroxide solutions as an alkaline activator. To this aim, alkali-activated natural pozzolan mortars were made with concentrations of sodium …

A Review Of The Hl-93 Bridge Traffic Load Model Using An Extensive Wim Database, Cathal Leahy, Eugene J. Obrien, Bernard Enright, Donya Hajializadeh

Articles

HL-93, the current bridge traffic load model used in the United States, is examined here. Weigh-in-motion from 17 sites in 16 states, and containing 74 million truck records, is used to assess the level of consistency in the characteristic load effects implied by the HL-93 model. The load effects of bending moment and shear force are considered on single-lane and two-lane same-direction slab and girder bridges with a range of spans. It is found that the ratio of WIM-implied to HL-93 load effect varies considerably from one load effect to another. An alternative model is proposed which achieves improvements in …