Recent Submissions

  • Application of glass and fan shells to a clay soil to increase its mechanical properties

    Jara, Heiner Lopez; Barrionuevo, Brandon Bravo; Díaz, Carlos Fernández (IOP Publishing Ltd, 2021-02-05)
    Improving the mechanical properties of a clayey soil is one of the best options to avoid future structural failures in buildings and is cheaper than replacing all the material. Therefore, this article proposes the use of recycled glass and fan shells as reinforcement materials. This article presents an experimental study to evaluate the mechanical properties of a pure and mixed soil. The clay soil was mixed with 7% of glass (PV) and with 3%, 6%, 10%, 12% and 15% of Fan Shells (PCA) duly crushed and passed through sieve #100. Tests of sieve granulometry, sedimentation granulometry, Atterberg limits, modified proctor and drained consolidated direct cut were performed. This allowed comparing all the data obtained and defining the optimal percentage of the mixture in which the clay improves its mechanical properties. According to the tests carried out, the proportion that has 7% glass and 6% Fan Shells has better results because there is an improvement in its dry density from 1,784 g / cm3 to 1,847 g / cm3, its moisture content increases from 9.4% to 12.1%. In addition, its friction angle improves from 28.9 °to 32 °and cohesion from 0.05 kg / cm2 to 0.1 kg / cm2. These results verify that the properties of the clay soil are improved.
    Acceso abierto
  • Sustainable urban pavement for cities affected by El Niño using porous concrete

    Aguirre, B.; Anchiraico, M.; Rodríguez, J.; García, F. (IOP Publishing Ltd., 2021-02-05)
    The El Niño phenomenon is caused by the change in atmospheric pressures, which produce the accumulation of hot surface waters on the eastern flank of the Pacific Ocean; causing intense rainfall that runs over the surface affecting the urban drainage of the city due to the lack of a permeable pavement; porous concrete allows infiltration of surface water runoff through its pores. The present investigation evaluates porous concrete in the range of w/c relationships of 0.30 and 0.32; the results indicate that the compressive strength, flexural strength and permeability coefficient increase; and that the surface runoff, cost, water footprint and carbon footprint are lower than conventional concrete.
    Acceso abierto
  • Evaluation of the Influence of Different Grades of Reinforcing Steel on the Seismic Performance of Concrete reinforced Frame Structures with Nonlinear Static Analysis

    Navarro, D.; Valero, R.; Orihuela, J. (IOP Publishing Ltd, 2021-02-04)
    In this investigation, the elasto-plastic behavior and the seismic performance of concrete reinforced frame structures reinforced are evaluated by applying the Pushover method. This evaluation is done on several cases: with high ductility steel (Grade 40), conventional steel (Grade 60) and high strength steel (Grade 75). For the previous, the capacity curve graph obtained from the displacement coefficient method was used to measure the capacity of the structure. In addition, the performance of the structure for different levels of seismic design are evaluated with the resulting values of ductility and rigidity of each case. The results showed that reinforcing a structure with a Grade 40 reinforcing steel increases the energy dissipation capacity, and if reinforced with a Grade 75 reinforcing steel increases the strength capacity in the structure. Finally, the comparative result of the various cases are presented to demonstrate the influence of reinforcing steel on the plastic behavior of concrete reinforced frame structures.
    Acceso abierto
  • Use of textile waste as an addition in the elaboration of an ecological concrete block

    Anglade, J.; Benavente, E.; Rodríguez, J.; Hinostroza, A. (IOP Publishing Ltd, 2021-02-05)
    The textile industry has grown significantly in recent years, reaching a global fiber production of 53 million tons which 12 % are recycled; Construction sector has been using more and more recycled materials from different industrial sources, to apply them in their constructions and to reduce CO2 emissions and final energy consumption. The present study aims to study the behavior of concrete blocks of fć= 210 kg/cm2 adding polyester textile waste with 3 %, 6 %, 9 %, 12 % and 15 %; void content, compressive strength and thermal conductivity decrease, and water absorption, acoustic insulation and unit price increase by 3 %, 34 % and 16 % compared to conventional concrete block.
    Acceso abierto
  • Concrete cracking control in underwater marine structures using basalt fiber

    Quispe, C.; Lino, D.; Rodríguez, J.; Hinostroza, A. (IOP Publishing Ltd, 2021-02-05)
    The construction of coastal ports requires the use of materials that meet the demands of the marine environment, to prevent underwater concrete structures from cracking and spalling easily; basalt fiber is used to delay the expansion of concrete and prevent the formation of cracks. This research studies the behavior of concrete for prefabricated piles with Portland Cement Type I and basalt fibers added in 0.1%, 0.3% and 0.6%; the results indicate that the fiber is suitable for concrete, the slump decreases, the compressive strength increases for specimens cured in tap water and sea water, the relationship between resistances does not vary, and the depth of carbonation decreases.
    Acceso abierto
  • Rheological, mineralogical and strength variability of concrete due to construction water impurities

    Awoyera, Paul O.; Awobayikun, Oyinkansola; Gobinath, Ravindran; Viloria, Amelec; Ugwu, Emmanuel I. (Trans Tech Publications Ltd, 2020-01-01)
    Various national and international standards recommend potable water for mixing concrete; however, the availability of potable water is virtually a daunting task in some developing communities. Concrete workers in such environments tend to utilize any available water for mixing concrete, and this may be detrimental to the quality of the concrete being produced. This study investigates the rheological, mineralogical and strength variability of concrete due to construction water impurities. Water samples were collected from four different construction sites within Southwestern region of Nigeria for production of concrete. The physical and chemical properties of the waters were determined so as to measure their rate of contamination, prior to their use for mixing concrete. The rheological properties of the fresh concrete, compressive strength, split tensile strength, and microscale features of hardened concrete, that were produced with each water sample were determined. From the results, the rheological features of concrete were found not to be affected by water impurities, however, the mechanical test results revealed about 10% reduction in strength between concrete made with water having least and higher concentration of impurities. Also, it was evident from the microscale tests that the water impurities do alter the hydration rate of concrete, which results in strength reduction. The study suggests pretreatment of concrete mixing water before use in order to avoid its damaging effect on concrete life.
    Acceso restringido temporalmente
  • A Geometric Design of Traffic-Light Roads Crossing Using the Continuous Flow Intersections Methodology to Reduce Points of Primary Conflicts Caused by Left Turns

    Chuco, Betsi; Pérez, Carlos; Silvera, Manuel; Campos, Fernando (2021-01-01)
    The continuous flow intersections (CFI) increase the operational capacity of road systems with congestion problems, by using shared lanes located at the access points before the intersection. However, the CFI presents road safety risks that increase the likelihood of vehicle collision. This article proposes a geometric design composed of raised delineators at a traffic-light intersection, whose objective is to eliminate the points of primary conflicts caused by the left turns of the vehicles. To do this, a study was conducted to identify the different maneuvers present in a wide cross-type intersection in a commercial area located in the city of Lima. A total of 3219 vehicles was collected, of which 561 vehicles turned left demonstrating the high density of this type of maneuver. The effectiveness of the proposed design is validated using a microsimulation in the Vissim program. The results show that it was reduced from 58 to 8 points of conflict, increasing operational capacity by 34.97%. Finally, the risks caused by CFI decreased by 83%.
    Acceso restringido temporalmente
  • Daily Control System for the Construction of Multi-family Building Projects

    Fernandez, Diego; Zamora, Yeffry; Rodriguez, Sandra; Vilcapoma, Jorge (2021-01-01)
    Construction projects for buildings, in the execution stage, show a variation of the real with respect to what is planned in the budget. The consequence of this lag presented usually causes large economic losses. Given this situation, in the construction industry, various control systems have been developed that have as a final deliverable a frequent management report, which serves to make decisions regarding the analyzed, whose results are applied and evaluated after a specific period of time. These management reports have good results at the time of their application; however, data processing, analysis execution, and decision making take approximately 30 days. In this sense, the present investigation proposes to develop a control system focused in real time, generated by the daily control in the execution stage. The results show a reduction of waste in the main resources of multi-family building projects, and this is in labor and materials, identifying the causes that originate them and suggesting generic solutions, at the end of the workday.
    Acceso restringido temporalmente
  • Use of Data Acquisition Technologies to Optimize Construction Progress Monitoring Times in Residential Buildings

    Aronés, Marisol; Mendoza, Andrea; Rodriguez, Sandra; Ramirez, Humberto (2021-01-01)
    The monitoring systems that are currently used as part of the management of construction projects consist of collecting the field information, documenting it manually and then digitizing it. Those responsible for carrying out the reports through this procedure dedicate between 28% and 41% of their time daily for their preparation. This traditional process is slow and inefficient because the information is dispersed in different documents, so data can be omitted, causing that no corrective actions are taken in a timely manner. Likewise, the construction sector has little use of technological resources, and therefore, there is no automated process, which makes it difficult to monitor construction projects in an efficient way. In this sense, this research establishes the optimization of the control procedure through the use of a data acquisition tool to reduce the man-hours used in advance control. With the application of this proposal, the hours spent by the personnel involved in project management were reduced by 30%.
    Acceso restringido temporalmente
  • Microsimulation of Public Transport Stops for the Optimization of Waiting Times for Users Using the Social Force Model

    Mendoza, Francis; Tong, Mayling; Silvera, Manuel; Campos, Fernando (2021-01-01)
    Cities in the world aim to ensure the mobility of people, through the implementation of efficient Integrated Transportation Systems (ITS). This aims to improve the transport of people, which guarantees that they can be mobilized safely and without delays in the terminals and bus stops of the public transport system. The present article proposes a design of public transport stops aimed at optimizing the waiting time of users when transferring from one bus to another. For the validity of the proposal, the social force model of the Vissim program was used, where the behavior of the users within the bus stops was reflected. The results showed that the waiting times in the calibrated and validated microsimulation model were optimized by approximately 20%, which generates an improvement in the efficiency of the public transport system.
    Acceso restringido temporalmente
  • Dynamic Amplification Factor Proposal for Seismic Resistant Design of Tall Buildings with Rigid Core Structural System

    Quezada, Eder; Serrano, Yaneth; Huaco, Guillermo (2021-01-01)
    Currently, there is an increase in the demand for tall buildings in the city of Lima. This research proposes to reduce the dynamic amplification factor through the seismic design of tall buildings based on the requirements of Peruvian code considering that they are regular in plan and height. Minimum base shear values according to the comparison of static seismic shear and dynamic shear from the spectral modal analysis were reviewed for cases of buildings larger than 120 m. The study of 28 reinforced concrete buildings was proposed, with different heights - varying from 24 to 36 floors, with different floor configurations, as well as the arrangement of the walls considering as a rigid core structural system. Additionally, the characteristics of the materials, the loads and combinations were defined. The responses of these buildings were determined by the response spectrum analysis (RSA) and then compared with those obtained by the lineal response history analysis (LRHA), for the last analysis, five Peruvian seismic records were used and scaled to 0.45 g. The seismic responses of the LRHA procedure were taken as a benchmark. The result of this study is the analysis and proposal of the C/R factor for high-rise buildings, as well as obtaining the base shear and drift verification. Minimum base shear values can be reduced for high or long-term buildings, being regular in plan and height.
    Acceso restringido temporalmente
  • Analyzing investments in flood protection structures: A real options approach

    Gomez-Cunya, L. (Elsevier Ltd, 2020-02-01)
    The soaring number of natural hazards in recent years due largely to climate change has resulted in an even higher level of investment in flood protection structures. However, such investments tend to be made in the aftermath of disasters. Very little is known about the proactive planning of flood protection investments that account for uncertainties associated with flooding events. Understanding the uncertainties such as “when” to invest on these structures to achieve the most optimal cost-saving amount is outmost important. This study fills this large knowledge gap by developing an investment decision-making assessment framework that determines an optimal timing of flood protection investment options. It combines real options with a net present value analysis to examine managerial flexibility in various investment timing options. Historical data that contain information about river water discharges were leveraged as a random variable in the modeling framework because it may help investors better understand the probability of extreme events, and particularly, flooding uncertainties. A lattice model was then used to investigate potential alternatives of investment timing and to evaluate the benefits of delaying investments in each case. The efficacy of the proposed framework was demonstrated by an illustrative example of flood protection investment. The framework will be used to help better inform decision makers.
    Acceso restringido temporalmente
  • Evaluation of the Evacuation of Essential Buildings: Interaction of Structural and Human Behaviour through Nonlinear Time-History Analysis and Agent-Based Modelling

    Delgado, M. (Institute of Physics Publishing, 2020-02-07)
    In this article, a performance assessment of the evacuation system is established for educational buildings. Structural and geotechnical information of the building is collected and introduced into a database. A similar procedure was realized for the information related to the occupants. Using this information, a) the structural fragility and localized collapse were determined and b) the interaction of the person with the partial collapse was established. For the first aspect, nonlinear time history was used, and for the second, the agent-based modeling was applied to recreate the reaction of people that face the micro collapse. Therefore, the important results of this evaluation are: 1) To localize collapsed beans and columns that make inoperable evacuation routes, 2) to localize bottleneck areas that people concentration during evacuation, and 3) quantification of affected people, in terms of persons caught up in the building that cannot evacuate.
    Acceso abierto
  • Mechanical Splices for Seismic Retrofitting of Concrete Structures

    Huaco, G. (Institute of Physics Publishing, 2020-02-07)
    As an alternative to lap splicing, mechanical splices can be used for retrofit purposes. They are generally most economical than traditional lap splices when available spacing or length makes laps difficult to utilize. Mechanical splices are frequently used in new construction. However, their use is limited and not practical for use in retrofitted structures. However, if the bars to be joined do not need to be threaded in order to be connected with a special mechanical splice, such mechanical splices can be useful. It is presented a proposal of using two types of mechanical splices for retrofit purposes. Cycle Tension and cycle tension-compression tests are presented and discussed. It was found that mechanical splices are suitable and have acceptable response under seismic loads.
    Acceso abierto
  • Bending Analysis of Nonlocal Functionally Graded Beams

    Garbin, F. (Institute of Physics Publishing, 2020-02-07)
    In this paper, we study the nonlocal linear bending behavior of functionally graded beams subjected to distributed loads. A finite element formulation for an improved first-order shear deformation theory for beams with five independent variables is proposed. The formulation takes into consideration 3D constitutive equations. Eringen's nonlocal differential model is used to rewrite the nonlocal stress resultants in terms of displacements. The finite element formulation is derived by means of the principle of virtual work. High-order nodal-spectral interpolation functions were utilized to approximate the field variables, which minimizes the locking problem. Numerical results and comparisons of the present formulation with those found in the literature for typical benchmark problems involving nonlocal beams are found to be satisfactory and show the validity of the developed finite element model.
    Acceso abierto
  • Performance Seismic Design of the Retrofit of a University Library using Non-Conventional Methods

    Chavez, B. (Institute of Physics Publishing, 2020-02-07)
    This research proposes a structural retrofit of a reinforced concrete building older than 50 years. The structural system is dual using frames and walls, having an area of 1980 m2 and 4 levels with a total height of 15.50 m. There are three unconventional methods to retrofit this infrastructure. The first is to install steel jackets with bolt anchors. The second methodology is through the use of jackets and anchors of Carbon Fiber Reinforced Polymers (CFRP). The third alternative is through reinforcement of walls with 2 diagonal struts made with CFRP sheets as struts, also installing CFRP anchors at each end of both struts to ensure that these sheets work up to their high levels of tension. These anchors together with the diagonal plates contribute to give ductility to the wall and in turn resist the effects of sliding at the base, a fault that is very common in rigid structures such as walls. Each unconventional reinforcement methodology used in this research is validated using laboratory tests results of reinforced columns and walls retrofitted with every of the three innovative methods. Nonlinear static analysis - Pushover of each alternative was performed and compared with the demand for the 1974 earthquake in Lima, scaling 3 seismic records to a PGA of 0.45g, which is the acceleration of design in Lima. It is shown that these proposals are effective in providing levels of shear base and displacement capacity in the inelastic design. For the 0.40mx0.80m columns, the results show that both reinforcements increase ductility by more than 10%; on the other hand, the proposal of reinforcement in the walls of 40cm thick, produced even better results increasing ductility by 100% and shear base by 100%.
    Acceso abierto
  • Nonlinear elastic analysis of concrete beams based on the Smeared Crack Approach

    Betancourt, N. (Institute of Physics Publishing, 2020-02-07)
    In the present study, an analysis of plain and reinforced concrete beams under monotonic loading was made based on the Fixed Smeared Crack approach. The objectives of this research were to analyze the nonlinear behavior of the selected cases of analysis and to propose an alternative and simple model for the analysis of beams under service loadings, by means of Committee 435 of the American Concrete Institute. A brittle model for concrete and a linear-elastic behavior for steel reinforcement bars were considered. Results are presented through force-displacement curves and the sequence of cracking propagation. Also, a comparison of calculated instantaneous deflections of simply supported beams was made between the proposed model and other researches. It was verified that the proposed algorithm can predict adequately the cracking process and the deflections of beams subjected to service loadings, taking into account experimental results from other authors.
    Acceso abierto
  • Proposal of Flowable Fill Designs for improvement of excavation and filling works of trenches in sanitation systems

    Cruz, J. (Institute of Physics Publishing, 2020-02-28)
    Population grow in recent years requires an extension of the current pipeline sanitary system. For this purpose, granular excavation and landfill works are associated with pedestrian traffic congestion. Therefore, it is necessary to develop an innovative and sustainable alternative to reduce the problems generated during the execution of the conventional process. This research proposes the use of flowable fill due to the multiple advantages offered by this material. On the one hand, it is economical for medium to large trench fill volumes, considering savings in labor (it is done with a small number of workers), in equipment (does not require the rental or purchase of compaction equipment) and in time (the pouring is done by directly pumping the mixture, from the mixing machines to the excavation). On the other hand, being self-compacting and self-leveling decreases the width of the trenches, reducing excavation and filling volumes; which, in turn, incur money savings. Also, this material guarantees work safety, since people are not required inside the excavation and fill in poorly accessible areas without any problem. Dosages were established for ten flowable fill mixtures with cement contents of 50, 60, 70, 80 and 90 kg of cement and a range of admixture from 1.75 to 2.00%; The results indicated that decreasing the fine aggregate - coarse aggregate ratio, the compressive strength of the mixtures increases and the slumps of the mixtures decreases, and the compressive strength increases directly proportional to the cement content.
    Acceso abierto
  • Stabilization of clayey soil for subgrade using rice husk ash (RHA) and sugarcane bagasse ash (SCBA)

    Hidalgo, F. (Institute of Physics Publishing, 2020-02-28)
    This document studies the stabilization of the soil used as a subgrade, by adding locally available materials such as rice husk ash (RHA) and sugarcane bagasse ash (SCBA). These aggregates were added to the soil in substitution by weight between 5%, 7.5% and 10%. By adding these, the expansiveness is reduced while the maximum dry density increases, in addition the tendency of CBR is increasing and then tends to decrease proportionally to the addition of the aforementioned aggregates. This indicates a peak in CBR and expandability. The best result obtained from CBR was 33.75% with the 5% replacement mixtures.
    Acceso abierto
  • Cracking Control in Mezzanine Floor Slabs using Rice Husk Ash and Polypropylene Fibers

    Cano, B. (Institute of Physics Publishing, 2020-02-28)
    The continuous population increase in recent years requires a greater number of households to be built quickly, with good materials and produced under quality standards that guarantee their manufacturing process. The prefabricated concrete, produced and supplied by concrete plants, is poured into the different structural elements, the mezzanine slabs being the most careful surfaces in the appearance of fissures; because being horizontal and having larger dimensions, the dimensional changes in the concrete appear more frequently due to the rapid loss of water from the surface of the concrete before setting; which generates superior stresses to the resistant capacity of the concrete at early ages, which affect the durability and reduce the resistance of the structures, causing greater economic expenses in maintenance and repairs. In the present investigation, 5%, 10% and 15% of rice husk ash was used as a replacement for cement and 900g/m3 of polypropylene fiber; The results indicate that as the percentage of rice husk ash increases, there is a reduction in the slump and the crack fissures, and that the resistance to compression and flexion decreases, with respect to the concrete pattern.
    Acceso abierto

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