Structural Engineering Commons^™

Early-Age Strength And Failure Characteristics Of 3d Printable Polymer Concrete: Numerical Modelling And Experimental Testing, Mohammad Amin Dehghani Najvani

Civil Engineering ETDs

The time-dependent rheological and early-age strength parameters of Polymer concrete (PC) were investigated. PC flow decreased, and the static yield stress and thixotropy increased as the specimen aged, while the dynamic yield stress remained unchanged. The study found that the Herschel-Bulkley model can accurately describe the PC’s rheological behavior over time. The change in cohesion strength and internal friction angle over time was observed using uniaxial unconfined compression and direct shear tests of fresh PC. A time-dependent MohrCoulomb failure criterion was established. Temperature analysis was used to determine the gel time and explain the evolution of the time-dependent early-age strength …

3d Printing Of Earthen Materials: Toward The Carbon-Zero Construction, Shiva Bhusal

Civil Engineering ETDs

In recent years, digital manufacturing techniques in the architecture and construction industry have rapidly gained attention, especially with 3D printing, also called additive manufacturing. The use of cement has been common in modern construction and is now being explored for 3D printing. However, due to cement's contribution to approximately 7 percent of global carbon emissions and its high cost, research on sustainable and greener materials has gained attention. Previous studies on alternative construction have examined the mechanical and rheological properties of soil mixes, but not much attention has been given to printability evaluation, shrinkage, and cracking, which can affect the …

Additive Manufacturing Of Engineered Cementitious Composites With Ultra-High Tensile Ductility, Amir Bakhshi

Civil Engineering ETDs

One of the critical factors in the development of additive manufacturing in the construction industry is designing suitable materials for 3D printing applications. 3D concrete printing (3DCP) has gained significant attention due to the abundance and availability of concrete. However, concrete is a brittle material and, without proper reinforcement, cannot meet the requirements for structural purposes. Engineered Cementitious Composites (ECC), known for high ductility, and strain-hardening with low fiber contents, can potentially eliminate the need for steel reinforcement in 3D printing without any need for manual placement of reinforcement. A set of systematic tests on ECC mix designs' fresh and …

Experimental And Numerical Investigation Of 3d-Printed Viscoelastic Dampers, Mohammed Jaradat

Civil Engineering ETDs

Elastomeric materials are extensively used in energy dissipation applications to mitigate large lateral displacements and attenuate vibrations. One way of exploiting the capabilities of elastomeric materials is using shear-damping mechanisms such as viscoelastic damping devices (VEDs).

In this research the freedom of design offered by additive manufacturing technology is utilized to produce 3D printed elastomeric parts that act as the viscoelastic layer in an energy damping device. A mechanically interlocked viscoelastic damper (MIVED) with a jigsaw-like interlocking mechanism was designed and manufactured. MIVED is composed of a rigid and soft phase. It operates in two modes, modes I and II, …

3d Printed Concrete & Polymer Concrete For Infrastructure Applications, Daniel Heras Murcia

Civil Engineering ETDs

Additive manufacturing technology has been established as one of the fastest-growing building technologies worldwide. Three-dimensional concrete printing (3DCP) has developed an increasing interest in the last decade due to its prospects as a transformative technology for industries such as the concrete precast. Besides the improvements in automation technologies in construction, traditional construction has faced considerable challenges: high accident rates, labor dependency, significant potential for automation, and high costs associated with the use of traditional formwork. In this context, three-dimensional concrete, also referred to as physical prototyping, is a novel construction technique in which the concrete is extruded layer-to-layer. 3DCP is …

Visualization Of Real-Time Displacement Time History Superimposed With Dynamic Experiments Using Wireless Smart Sensors And Augmented Reality, Marlon Frank Agüero Injante

Civil Engineering ETDs

Wireless Smart Sensor (WSS) process field data and inform structural field engineers and owners about the infrastructure health, condition, and safety. Engineers acquire the data and investigate changes on displacements under loads to make informed choices and prioritize decisions concerning maintenance, required repairs, and infrastructure replacements. However, reliable data collection and access to displacement information in the field in real-time under loads remains a challenge. The displacement data provided by the WSS in the field undergoes additional processing, and it is seen at a different location, at the decision-making headquarters. If inspectors were able to observe structural displacements in real-time …

Retrofit Of Corroded Corrugated Metal Culverts Using Gfrp Slip-Liner, Rahulreddy Chennareddy

Civil Engineering ETDs

Culverts are water conveyance structures, typically used to allow water flow and maintain a balance between the flow streams without interrupting structures such as highways and bridges. Corrugated metal pipes (CMPs) have been used as culverts in North America since the 1950s because of their low cost and simple construction method. Today, the corrosion of CMPs is a major problem faced by all U.S. Departments of Transportation. There is an urgent need to provide an efficient solution, one that is corrosion-resistant, to retrofit thousands of corroded CMPs across the country. High specific strength, high strength to weight ratio, corrosion resistance, …

Validation Of The State Based Peridynamic Lattice Model, Anima Bista

Civil Engineering ETDs

This thesis presents a study performed to validate the State-based Peridynamic Lattice Model (SPLM) using results obtained from laboratory experiments. The SPLM is capable of modeling cracking of solids using particle lattices. We use a plane stress, elastic-plastic damage SPLM model for the simulations. The SPLM model is appropriate for computational simulations of cementitious materials as it automatically allows cracks to develop. In this study, the lattices are rotated through different angles and the variations of the cracking patterns are studied. In the laboratory, we performed nine Brazilian split cylinder tests, three anchor pullout/direct tensile tests, and eight compression tests …

Elevated Temperature Progressive Damage And Failure Of Duplex Stainless Steel, Darren P. Luke

Civil Engineering ETDs

Ductile failure of metals has been the focus of research efforts within academia and industry for many years since it is tremendously important for understanding the failure of structures under extreme loading conditions. However, limited research has been dedicated to elevated temperature ductile failure, which is critical for evaluating catastrophic events such as industrial, structural or shipping vessel fires. A detailed investigation was conducted on the structural response of Duplex Stainless Steel at elevated temperatures. The temperature dependence of elastic modulus, yield strength, ultimate strength, and ductility was measured up to 1000°C and a continuum damage plasticity model was developed. …

Cementitious Sensors Exhibiting Stopbands In Acoustic Transmission Spectra, Shreya Vemuganti

Shared Knowledge Conference

Ultrasonic monitoring in cementitious materials is challenging due to the high degree of attenuation. In wellbore environments, monitoring becomes more challenging due to inaccessibility. Meta materials, also known as acoustic bandgap materials, exhibit an interesting feature of forbidding the propagation of elastic/sound waves and isolate vibration in a certain frequency band. Traditionally, acoustic bandgap materials are developed with inclusions such as tin, aluminum, gold, steel in a polymer matrix. In this study, we present the development of three-dimensional cementitious sensors capable of exhibiting stopbands in the acoustic transmission spectra using carbon nanotubes. Relatively wide stopbands were engineered using Floquet-Bloch periodic …

Characterization And Modeling Of Asphalt Concrete For Dynamic Properties And Performances, A S M A. Rahman

Civil Engineering ETDs

The recently developed mechanistic-empirical pavement design guide (MEPDG, also known as Pavement M-E design method) uses the nationally calibrated, binder viscosity-based dynamic modulus predictive model for the design and analysis of asphalt pavements. In this study, this model is assessed for its appropriateness for asphalt-aggregate mixtures typically used in New Mexico. In essence, this study investigates the predictability issue of complex modulus of New Mexico mixes. A total of 54 Superpave mixes with different aggregate gradations, air voids, and binder grades were collected from the mixing plants and from the pavement construction sites. The loose asphalt mixtures were then compacted, …

State-Based Peridynamic Particle Method, Siavash Nikravesh Kazeroni

Civil Engineering ETDs

In this study, a novel discrete Peridynamics framework called the “State-Based Peridynamic Particle Model (SPPM)” is introduced. In this approach, a solid body is simulated by neither solving differential equations nor integral equations; instead, the simulation is accomplished by directly solving discrete systems of equations using finite summations. SPPM is formulated for a random distribution of particles, hence, it can be considered as a meshfree method. The assumptions of continuity and homogeneity are not necessary for this approach. The SPPM is a generalization of the “State-Based Peridynamic Lattice Model (SPLM)”. In the SPLM formulation, for sake of simplicity and computational …

Characterization Of Unknown Bridge Foundations, Saman Rashidyan

Civil Engineering ETDs

The National Bridge Inventory (NBI) recognized 86,133 bridges in the United States have no foundation data on record in 2003. It is evident that an unknown percentage of the 86,133 bridges identified by NBI with missing foundation data could also be highly vulnerable to scouring induced by water flow coupled with erodible soils. Conventional excavation, coring and boring excavations to identify unknown bridge foundation depths and types are deemed to be expensive, destructive, and limited in their application to the unknown foundation problem. Many surface and borehole nondestructive testing (NDT) technologies have been developed for this purpose. Three economical proven …

Practical Considerations In Determining Timber Pile Depth Using The Sonic Echo Method, Ali F. Jwary

Civil Engineering ETDs

The Federal Highway Administration indicates that about 85,000 bridges in the United States have no original contract documents with information about the type, depth, geometry and material of their foundations (FHWA, 2010). Furthermore, the National Bridge Inventory (NBI) provides information about 86,133 bridges nationwide that are rated as scour critical because of unknown foundation condition. In New Mexico, there are more than 281 bridges with unknown foundations, which are owned by the New Mexico Department of Transportation; 71 of these are timber bridges. These data indicate a serious problem that needs decisive action to assess the unknown bridge foundation characteristics …

Proceedings Of The First International Conference On Smarandache Multispace & Multistructures, Florentin Smarandache, Linfan Mao

Branch Mathematics and Statistics Faculty and Staff Publications

In recent decades, Smarandache’s notions of multispace and multistructure were widely spread and have shown much importance in sciences around the world. Organizedby Prof.Linfan Mao, a professional conference on multispaces and multistructures, named the First International Conference on Smarandache Multispace and Multistructure was held in Beijing University of Civil Engineering and Architecture of P. R. China on June 28-30, 2013, which was announced by American Mathematical Society in advance.