All projects are sub-sets of larger projects that are ongoing at AIDICO. The projects cover a wide variety of extreme events, including natural, man-made and/or accidental hazards. The research novelty of the projects is apparent from the description in the following. Therefore, the research is likely to significantly expand the boundaries of existing knowledge base on hazard mitigation of infrastructure, and result in products that may have wide application in practice.
Durability of Concrete Under Flood Conditions
Hazard Type: Flood (natural)
2014 Student Participant: Kavitha Ramaswamy, Civil Engineering, UT Arlington
Prolonged exposure to water under natural flood conditions, especially in aggressive environments with high water salinity and/or high temperature, may accelerate corrosion of steel within reinforced concrete structures and promote concrete deterioration. The effects of water seepage in concrete are as follows: (1) induces capillary formation leading to spalling of concrete; (3) reduces the overall strength of concrete; (5) reduces durability. In this project, the student will work at the AIDICO Basic Materials Laboratory to perform research on the durability aspects of concrete marine structures and also structures that are subjected to extensive flooding conditions. The following tasks will be undertaken: (1) Review of basic concrete design technology and U.S./European concrete durability testing procedures; (2) Select parameters for durability testing, such as concrete mix design; (3) Perform several types of concrete durability tests, as follows: (a) Water permeability (AENOR 12390 2001); (b) Porosity (ASTM C-642 2006, IRAM 1871 ?); (c) Rapid chloride permeability (Nordtest 1999); (d) Carbonation accelerated (AENOR 13295 2005); and (e) Autogenous shrinkage (AIDICO internal procedure). The tests will be performed on concrete samples that are submerged in saline water with elevated temperature for about three weeks. The tests will indirectly measure the long-term durability and corrosion potential in concrete with prolonged water submersion in an aggressive environment; (4) Compare test results with those from control samples with no aggressive exposure; and (5) Formulate recommendations, based on the test results.
Nano-coatings for Nuclear Meltdown Containment
Hazard Type: Nuclear meltdown (accidental)
2014 Student Participant: Abin Abraham, Civil Engineering, Prairie View A&M University
The U.S. currently intends to provide a reliable storage of nuclear wastes in a below ground repository for a period exceeding 10,000 years. While there are many solutions for reliable protection of the waste material from accidentally contaminating the environment, a particular challenge is corrosion of the waste package in the repository. Use of inorganic coatings on metallic substrates would provide significant cost savings to the waste package design and mitigate aggressive corrosion conditions. The incorporation of carbon nano-materials can reinforce both the mechanical properties and the thermal stability of the final coatings. The objective of this project is the development of a geo-polymer based coating for nuclear waste containment in order to fit the following properties: High mechanical properties (60 -100 MPa); corrosion resistance under a simulated waste salt solution at 90 ºC, and resistance to lixiviation of simulated waste salt solution at 90ºC.
The following specific tasks will be undertaken: (1) Review state of the art literature about the use of nano-materials and inorganic binders for nuclear meltdown containment. Focus will be on carbon nano-fiber and nano-tubes, and alumino-silicate and silicate based binders with ability to resist high temperatures; (2) Prepare simulated waste salt solutions using different contaminants; (3) Formulate a fly ash based geo-polymer composite coating material with addition of carbon nano-particles. A Class F fly ash powder will be mixed sequentially with sodium silicate, sodium hydroxide and water, together with nano-materials. Mixing will continue until the mixture develops into a cohesive mass; (4) Characterize the coating with regard to mechanical properties. The mineralogy, morphology and structure will be studied through X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Optimal 48 hour compressive strength of about 60 MPa (about 100 MPa with nano-materials) is desirable; (5) Determine corrosion resistance by electrical impedance measurements made on sections of the coated steel samples; (6) Test durability by leach testing method specified in the EPA Toxicity Characteristic Leaching Procedure (EPA 2008); and (7) Analyze data gathered to confirm whether or not the desired products were obtained and the identified application product was durable.
Behavior of Precast Concrete Cladding in Extreme Wind Loads
Hazard Type: Extreme loads (natural, man-made, accidental)
2014 Student Participant: Toddrick Brown, Civil Engineering, Prairie View A&M University
Precast cladding or curtain walls are the most common use of precast concrete for building envelopes (Gaudette 2009). Common cladding units include wall panels, window wall units, spandrels, mullions, and column covers. They do not transfer vertical loads but simply enclose the space, and are only designed to resist wind (occurring naturally), seismic forces, and their own self weight. However, cladding connections to the main structural framing can allow the cladding system to carry additional loads (Gaiotti and Smith 2003). In this project, a theoretical research approach will be used to investigate the cladding-framing interaction. The following research tasks will be undertaken: (1) Review the current precast cladding design methodology from relevant standards (Euro Code 2 2006, PCI 2007). Both U.S. and European techniques will be explored; (2) Select a typical medium height building with a moment resisting framing system and typical precast concrete cladding with a decorative stone facing and a separating air. The panels will be full-story high, and connected to the structural frame by steel haunch bearing connections; (3) Perform basic finite element analysis for a building located in Valencia, using the software RISA 3D, with only dead loads, live loads and expected design wind loads (RISA is currently the most widely used structural analysis/design program in the world); (4) Compare the loads and deflections carried by the main framing system and the cladding for two cases: with cladding-framing interaction and without such interaction; and (5) Evaluate the effect of the modified loads for the real life interaction case on the design of the cladding and the framing system.
Fire Resistance of Building Elements
Hazard Type: Fire (natural, man-made, accidental)
2014 Student Participant: Toul Deguia-Crammer, Pre-Engineering, Lone Star College
This project is designed to improve the student’s knowledge on the behavior of different construction products and elements subjected to fire. Fire can be caused naturally (wildfire), deliberately (arson) or accidentally. These products are: doors, load bearing elements (beams, columns, roofs, ceilings), non-load bearing elements (walls, ceilings, curtain walling), service installations, mortars, and protective coatings. The student will undertake the following research tasks: (1) Review relevant technical standards for fire resistance test, fire classification of construction products and building elements, fire resistance test for non-load bearing elements, fire resistance test for load-bearing elements, fire resistance and smoke control test for door, shutter, and openable windows, assemblies and elements of building hardware, tests for service installations, and tests for determining the fire resistance of structural members; (2) Learn experimental and analytic methods to assess the fire resistance for products/elements used in construction. The test method used will be based on requirements specified in European standards for configuring the test sample, preparing supporting construction (rigid or flexible) for samples, instrumentation with thermocouples, extensometers, and testing with the specified fire curves generated through a furnace, and measuring all relevant parameters (EN 13631-1 2005); (3) Develop new test methods for fire design, taking into account the variables in a fire situation; and (4) Use software application based on CFD (computational fluid dynamics) to assess the fire resistance of the buildings or others constructions. These applications are based on computational model simulation of fire, using random methods to introduce the variables in the mathematical functions. Specifically, the student shall use the ATENA software program used for fire analysis of concrete elements (Cevenka Consulting 2012).
Worker Fall Protection from Temporary Construction Equipment
Hazard Type: Construction worker fall (accidental)
2014 Student Participant: Kelsey Fort, Civil Engineering, UT Arlington
In the construction industry, accidental falls are the leading cause of worker fatalities. Each year, on average in the U.S.A., between 150 and 200 workers are killed and more than 100,000 are injured as a result of falls at construction sites (OSHA 2006). The construction industry has inherent risks from tasks such as roof work, scaffolding and use of ladders and it is these agents that account for the largest proportion of all work at height fatalities (QBE 2009). The research work will involve studying and proposing improvement measures to obtain better mechanical behaviour against impact loading on temporary work equipment used in construction projects. The student will study the nature of the materials, geometrical and mechanical characteristics of temporary work equipment used currently in building construction process. He/she will investigate the maximum dynamic pressures on such structures for impact loading; analysing the results in terms of safety level in different equipment and protections systems; and proposing measures to improve mechanical behaviour against impact loading on different equipment and fall protection systems. The following tasks will be undertaken: (1) Study the requirements of technical standards for assessing temporary work equipment and protective systems to prevent falls. This will include safety nets, temporary edge protection systems, personal fall protection equipment, anchor devices, mobile access and working towers; loading platforms; scaffolds; basis of structural design; steel and timber structures; (2) Learn about experimental and analytic methods to assess the impact resistance on equipment and systems used in construction process (listed in Task 1). The student will learn protocols for full-scale tests, equipment, instrumentation, specific software for recording and post-processing of data; and (3) Evaluate the behavior of a prototype fall protection equipment by numerical analysis and scale tests. Validate the design and propose necessary changes to improve impact behavior.
Non-Destructive Testing (NDT) and Wireless Monitoring for Seismic Risk Reduction
Hazard Type: Earthquake (natural)
2014 Student Participant: Ariel Deval, Civil Engineering, UT Arlington
The NDE and wireless monitoring are two excellent techniques for assessing the potential for seismic hazards and thereby mitigating against this natural extreme event. The following tasks will be undertaken for this summer IRES project: (1) Receive training in the basics of NDT, such as ultrasonic, Ground Penetrating Radar (GPR), inter-ferometric radar, and correlation of destructive and non-destructive testing. Detection of specific targets in a concrete cube using ultrasonic and GPR will be undertaken; (2) Receive training in the basics of structural health monitoring: physical principles, equipment and application cases, and implementation of wireless sensor networking (WSN) in the field and sensor lay-out; (3) Implement inter-ferometric radar and WSN in a specific structure (in a cable-stayed bridge) in the Valencia area. These two techniques have never been utilized simultaneously in a real structure for monitoring of indicators of potential seismic activity; (4) Acquire seismic related data from these two methods, including ground vibration; and (5) Compare acquired data from the simultaneous application with acquired data from the following two cases: only with inter-ferometric radar and only with WSN.