■ Meetings with the Supervisor to discuss two previous tasks:
The two previous tasks were delivered in the first ten weeks of the semester. The teacher asked for the quality of used sources. The sources used for the investigation were only scholar sources. Science Direct, Elsevier and Google Scholar were the used databases in the investigation. There are several paid databases where the investigator and university had no subscription. The previous databases offered more than one thousand results referred to composite piles design, but only twenty sources were selected for the investigation. The sources are in a level of master studies and philosophy doctor studies. The consulted sources had extensive reference list that confirmed the quality of the source.
The teacher confirmed the achievement of the project milestones; there was an agreement about the delivery of the investigation products once the information is ready with results and conclusions.
The teacher agreed to support with the availability of the material test laboratory in weekdays. The composite pile investigation requires test laboratory to confirm the mix qualities of concrete and steel. With the support of the teacher, it was possible to develop laboratory tests.
■ Analysis of key findings from the literature review
The literature review from scholar databases gave to the project the following key findings:
□ Definitions of composite piles and composition
□ Calculation methods for the design and manufacture
□ Strategies for the external force calculation. The use of vertical and lateral framework for calculation
□ Benefits and disadvantages of the use of composite piles over other materials as timber, wood, and steel (Civil Engineering Forum, 2014).
■ Achieved tasks during previous semesters:
Theory framework investigation: The first fifteen pages of the research project are composed of theory information about the composite piles. The use of previous research papers from databases and information from composite piles manufacturers gave to the project updated and trustable information about the geotechnical design of composite piles. The used criteria for the design of the composite piles depend on of the location where the composite piles are installed. The use of theory soil quality in different locations of the country gave valuable information for the investigation project. The mechanical behaviors of the composite piles depend on of the configuration of the matrix of the pile with the use of steel and concrete. Several consulted papers bring information about preparation and manufacture techniques for the composite piles and the mechanical behavior of the composite pile. The manufacture time affects the mechanical behavior of the pile. Similar to the fracture tests of the concrete, the composite pile must be manufactured and tested at different times to calculate the final mechanical properties of the composite pile.
Determination of behavior of the composite piles at vertical al lateral loads: The use of the theory framework and experimentation gave to the investigation valuable information about how the composite piles behave at different external conditions of force and natural conditions.
The use of the scheme of separated forces as vertical and lateral facilitated the study of the phenomenon because the vertical forces generate two phenomena: traction force and buckling of the composed body. The traction force is absorbed by the concrete matrix of the pile thanks to the physical and mechanic conditions of the mixed clinker of high compression yield. The buckling phenomenon occurs when the vertical force provokes a high compression of the pile moving the grain material to the horizontal plane. That phenomenon is possible to study it using the rules of the American Standard of Mechanical Engineers (ASME) and calculate the buckling of the pile. Both phenomena are possible with the vertical forces.
The lateral forces are studied separated for the vertical forces to facilitate the calculation. The vertical forces are mainly momentum forces that affect the grain of the composite pile generating stress and a momentum force translated to the base of the composite pile where has a fixed articulation avoiding the force to the other extreme of the pile, where the articulation with the bridge or application of the composite pile is free.
Both calculation results, vertical and lateral are added, resulting in a force and momentum with components in the three axes.
■ Environmental impact determination:
The study brings more benefits than disadvantages for the use of composite piles in the construction site. The concrete piles were compared with timber piles and steel piles. The concrete piles have the advantage that steel is inside the matrix of the pile protecting it from the abrasion and corrosion of the environment, dry and wet. The wood piles are less durable than the concrete piles with the potential consequence than the additives and chemicals used in the wood piles may react with the soil, different from the concrete piles that have fewer additives and are less reactive with the soil and water. The most important disadvantage of the concrete pile is the removal procedure of the same. It is necessary to demolish the pile from the base different to the steel piles, which has a bolt-and-nut fixation with the base.
Identification of milestones required to achieve the deliverables:
The milestones were identified according to the results and deliverables of each step. The milestones are divided into three important groups:
■ Theory framework information
■ Behavior of the composite pile with lateral and vertical forces.
■ Environmental effects of the composite piles.
Bibliography
Civil Engineering Forum, 2014. Pile Foundation | Concrete Piles, Steel Piles, Timber Piles and Composite Piles. [Online] Available at: http://civilengineersforum.com/pile-foundation-steel-piles-concrete-piles-timber-piles-composite-piles/ [Accessed: 19 May 2016].
