• Additional results on integrals of beam eigenfunctions

      Morales, César A; Facultad de Ingeniería, Universidad Peruana de Ciencias Aplicadas, Lima, Perú (SAGE Publications Ltd, 2018-03-14)
      New simplest expression beam mode integrals are presented, including further simplifications and corrections of previous results; this type of integrals appear in computational methods in structural dynamics and vibrations of diverse structures and machines, and in aircraft dynamics methods.
    • Analysis of high plasticity clayey soil improvement at subgrade level through Portland cement added to decrease volumetric change

      Castro, M. (Institute of Physics Publishing, 2020-02-28)
      This research includes the potential for resistance and the expansion that the soil presents, this evaluation was carried out through CBR tests. The soil cement technique was used to improve the physical and mechanical characteristics; this process consists in mixing the material with Portland cement type I. That combination forms soil cement 10%, 15% y 20%, which present an increase of the CBR (max: 138.7% and min: 91.9%) achieving a type of extraordinary subgrade to resist the structure of the pavement and a reduction of 7.18% in the expansion of the samples.
      Acceso abierto
    • 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
    • Association between Perceived Risk and Training in the Construction Industry

      Universidad Peruana de Ciencias Aplicadas (UPC) (American Society of Civil Ingenieers, 2015-05)
      Acceso restringido temporalmente
    • 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
    • Control of fissures generated by the retraction in rigid pavements, applying synthetic fibers of recycled polypropylene.

      Torres, V. (Institute of Physics Publishing, 2020-02-28)
      The retraction affects the setting process and the useful life of the concrete with the appearance of fissures; in last year's studies and methods have been generated to mitigate and control it with the use of different products and applications. The development of road infrastructure with the use of concrete as a rolling folder, requires methods to guarantee the durability and reduce the effects of the efforts incorporated by the use, climatic conditions, support base and restrictions of movement of the structure. To evaluate the effects of recycled synthetic polypropylene fibers in plastic retraction tests (ASTM C 1579), 3 mix designs were prepared with different ratios 58 gr., 116 gr., and 176 gr. of recycled and virgin synthetic fibers; the most significant and positive result to reduce fissures without affecting the resistance of concrete by bending and compression, was 0.50 mm without addition fibers, 0.10 mm and 0.15 mm with 176 gr. of virgin and recycled synthetic fibers. Finally, it can be concluded that adding a ratio of 4 kg per m3 allows good workability, in addition, the costs of the fibers are not representative compared to the high costs for future repairs.
      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
    • Eco-Concrete for Hydraulic Structures with Addition of Colloidal Nano-Silica

      Salguero, C. (Institute of Physics Publishing, 2020-02-28)
      In the construction of buildings and infrastructures, high resistance materials are used due to current design requirements, concrete being one of the main materials used in the execution of these projects whose cement content is limited to obtaining an economic concrete and of minimum retraction. This limitation requires the use of new additions such as Nano Silica (NS), which due to its nanometric structure is used as a partial replacement for cement, producing an increase in strength in concrete. The present investigation studies the partial replacement of the NS in the cement to determine its behavior in compressive strength, diametric compressive strength, water permeability coefficient. The results indicate that with an addition of 0.225% of NS the compressive strength and splitting tensile strength are increased and the water permeability coefficient decreases, all of them compared to a conventional concrete.
      Acceso abierto
    • Evaluation of the curvature ductility ratio of a circular cross-section of concrete reinforced with GFRP bars

      Pichardo, C. (Institute of Physics Publishing, 2020-02-28)
      The present study deals with the use of fiberglass reinforced polymer bars (GFRP) as a replacement for the common steel of a reinforced concrete circular pile, in order to avoid the corrosion of durability of reinforcing bars and thus improve them. The comparative analysis was carried out between a pile reinforced with GFRP and another with steel, where the ductility was evaluated by obtaining moment-curvature diagram. As a result, said idealized moment-curvature diagrams and ductility indices are presented, concluding the ductility of the section reinforced with GFRP in 20% more than that of steel.
      Acceso abierto
    • 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
    • Evaluation of the geotechnical behaviour of a volcanic soil wall with additions of lime and cement against landslides

      Davila, C. (Institute of Physics Publishing, 2020-02-28)
      The construction of earth walls can be a significant response to prevent the next landslides from reaching the road and avoid accidents. Therefore, a material of the same slope was used and reinforced with mixtures of lime and cement, with this same reinforced material a mechanically stabilized hypothetical earth wall (MSE) was developed. An analysis of the original slope was developed to check if there was a possible failure through its safety factor. Then, a hypothetical wall was developed with a floor reinforced with mixtures, in order to assess its overall safety factor and its maximum landslides. According to the results, in principle it was determined that the dosage M-3 / C-4-4 improves in a range of 30% to 37% the friction angle. In addition, it was found that a reinforced wall, that is to say with Lime and cement additions, presents a better behaviour. In its effect, its displacements are about 8 mm and have a global factor of 1.23.
      Acceso abierto
    • Experimental analysis of the addition of rice husk ash to the clayey subgrade of a road stabilized with lime

      Vizcarra, S. (Institute of Physics Publishing, 2020-02-28)
      There are many studies about how the addition of lime and rice husk ash (RHA) gives the soil a better mechanical behavior, particularly on clayey soils, where usually fine particles reach more than 75%. However, the soils with a small presence of fine particles (59-60%) do not have much research. This analysis evaluates the influence that RHA has on this kind of soil stabilized with 3% of lime. After the initial mix of soil-lime, CBR increased 11.2 times its initial value; within the addition of the ash, the CBR averaged between 45-50% up until 28% of RHA was added, where the results decreased considerably. Soil workability improved and the specimens with more ash resulted in a more granular material, with a group index value 0 following the AASHTO standards. The greatest CBR record was obtained with the specimen of 16% RHA, 3% lime and soil, reaching a 51.3% CBR, 1.58g/cm3 of MDD and 16.5% of OMC. Yet, it only showed a 1.55% more resistance than the lime-soil specimen. The CBR with more presence of RHA tends to decrease its value, therefore for silica-rich clayey soils, the addition of lime by itself should be enough for an adequate performance.
      Acceso abierto
    • Experimental study of the mechanical effect of a clayey soil by adding rubber powder for geotechnical applications

      Alvarez, N. (2020-02-28)
      At present, worrying quantities of tires are discarded due to the growth in demand for vehicles in the world, which has a direct impact on the deterioration of the environment since they normally go to landfills. Based on the background found, the use of this material for geotechnical applications can help reduce the pollution they generate and improve the physical and mechanical properties of soils. Therefore, this research seeks to evaluate a greater shear strength and capacity of support to the penetration of the clayey soil by means of the addition of 1.5%, 2.5% and 3.5% of rubber powder recycled. For this, the Atterberg limits analysis, the modified proctor compaction test, shear box and CBR were performed. For the shear box test, the results reflect that the cohesion of the mixture increased and the angle of internal friction decreased with respect to the natural soil, resulting in the sum in an increase of shear strength. On the other hand, the percentage of CBR increased, this means that the rubber helped the soil to be more rigid and have a greater resistance to penetration. These mixtures could be used in different projects within geotechnical engineering, as it presents an improvement in shear strength and an acceptable support index value (CBR).
      Acceso abierto
    • Hermite–Lagrangian finite element formulation to study functionally graded sandwich beams

      Universidad Peruana de Ciencias Aplicadas (UPC) (Elsevier B.V., 2016-04)
      This paper presents a static analysis of functionally graded single and sandwich beams by using an efficient 7DOFs quasi-3D hybrid type theory. The governing equations are derived by employing the principle of virtual works in a weak form and solved by means of the Finite Element Method (FEM). A C1 cubic Hermite interpolation is used for the vertical deflection variables while C0 linear interpolation is employed for the other kinematics variables. Convergence rates are studied in order to validate the finite element technique. Numerical results of the present formulation are compared with analytical and FEM solutions available in the literature.
      Acceso restringido temporalmente
    • Improvement of physical, mechanical and strength behavior of cohesive soils with natural pozzolana and brick dust

      Chang, E. (Institute of Physics Publishing, 2020-02-28)
      This research project seeks to improve soil properties through experimentation with geotechnical purposes. For this, will be used natural volcanic pozzolana in 5%, 10%, 15% and brick dust in 10% giving it a second reuse. The soil improvement will be analyzed with the proposed additions and its influence on the results. It is concluded that the addition improves the behavior of the soil by decreasing its plasticity index, increases the compaction index and improves the geotechnical parameters.
      Acceso abierto
    • An initial evaluation of a method for adopting kaizen events in the construction sector

      Arriola Oliveros B. (Potificia Universidad Catolica de Chile, 2018-04-01)
      Currently, construction companies have shown a need to adopt process improvement systems in order to function competitively in the market. However, civil construction, compared to the manufacturing, still has deficiencies relating to the incorporation of new improvement systems. Thus, the use of Kaizen Events (KE) is one of the main mechanisms used to perfect processes during the production (execution) phase of a product, ensuring enhanced performance and added value to the client. The present research sought to evaluate a method for adopting KE in the construction sector. The data-gathering tools used were a questionnaire and a focus group where academics and/or experts who fit a specific profile participated. A methodological strategy for the development of the work was adopted under the approach of Design Science Research (DSR) and the theoretical referential was developed from a Systematic Literature Review (SLR). Improvements were made to the method to improve its applicability and functionality in real life scenarios using the results obtained. Accordingly, the results show horizons for future research on KE in civil construction.
    • Low Permeability Concrete for Buildings Located in Marine Atmosphere Zone using Clay Brick Powder

      Castillo, M. (Institute of Physics Publishing, 2020-02-28)
      The concrete is not one hundred percent impermeable since the water that remains inside it causes its corrosion, in the case of reinforced concrete, exposed in an area of marine atmosphere, the sea salt mostly present in large particles of the marine spray, produce the reduction of the alkalinity of the concrete causing a rapid corrosion of the steel. There are buildings built in this marine area that have been designed without durability criteria, in which the use of pozzolanic materials is considered, for example, to fill the pores of the cement matrix and thus guarantee its impermeability. In the present study, the effect of clay brick powder (PLA) as a replacement for cement in concrete manufacturing is addressed, evaluating different characteristics of its components. The results indicate that pozzolanic activity and compressive strength increase, slump, voids content and the coefficient of permeability to water decreases.
      Acceso abierto
    • Mechanical properties and self-cleaning mortar capacity C/A 1: 5 of Portland cement modified with titanium dioxide (TiO2)

      Flores, H. (Institute of Physics Publishing, 2020-02-28)
      The deterioration of the surfaces of the constructions made with mortar C/A 1: 5 of Portland cement, are produced by being exposed to the emission of toxic gases emanating from the growing automobile fleet, this problem causes alternatives to be sought in order to counteract its effect on buildings and the environment. A new method to deal this problem is the incorporation of the titanium dioxide photocatalyst (TiO2) into the Portland cement mortar, which can develop self-cleaning and air purification properties to be in contact with sunlight. This work seeks to introduce this organic component to the Portland cement mortar, used for the facade charging and structural elements, for this purpose, different percentages (5%, 7.5% and 10%) of titanium dioxide (TiO2) are added and the properties of the modified mortars making use of [1] compression tests, [2] fluidity tests, [3] absorption tests and [4] photocatalytic activity tests with which the self-cleaning capacity was verified. This study concludes that the best percentage of titanium dioxide addition is 5%, with which the Portland cement mortar is granted self-cleaning property without substantially damaging its mechanical properties.
      Acceso abierto
    • Mechanical Properties of an Eco-friendly Concrete with partial replacement of POC and Rubber

      Espinoza, A. (Institute of Physics Publishing, 2020-02-28)
      Concrete plants consume 10 billion tons of natural aggregates annually from quarries and gravel plants for produce concrete, this demand requires exploiting natural resources from mountains and rivers producing an ecological imbalance. One solution is to use Palm Oil Clinker (POC), which is eliminated in large quantities in the dumps and rivers without taking advantage of its puzolanic, binding and resistance properties as an aggregate in the concrete; another alternative is to apply rubber from abandoned and discarded tires as waste in landfills or burned, without taking advantage of its performance of improvement in concrete, increasing its resistance to impact and fatigue. Unable to find joint POC and rubber information, this research studies its influence replacing 2.5% rubber (grained and crushed) with 10%, 12.5% and 15% POC in the fine aggregate on traditional concrete; results indicate that with 12.5% of POC as the ideal percentage, the compressive strength, tensile strength and flexural strength rise between 2.16 - 9.54%, so the concrete obtained has a cost of less than 4.09% and has 3.65% less CO2 emission.
      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