The Existence of Stilt Houses Post-Disaster

Stilt houses are one of the architectural identities of the archipelago that are still commonly found in Indonesia. Stilt houses have proven to be sustainable products because they still exist today after going through various natural disasters. This is inseparable from the stilts house building techniques, including the process of finding and determining the form and implementation of adat (philosophy). So, this research aims to show the existence of post-disaster stilt houses which include tsunami disasters in Aceh and Palu. This research is a case study that uses a comparativeanalysis method to show the influence factors of the existence of stilts houses after disaster in Aceh dan Palu. Based on the results of the study, it is known that the stilt houses in Aceh and Palu have stilt buildings that are sturdy and stable in accepting the force load when a disaster occurs. The key of building sturdiness lies on building structures such as connection systems, foundation type, material type, and the buildings proportion. These factors caused the stilts houses to not suffer severe damage, and in some cases did not show any damage to the buildings after being affected by natural disasters.

Predicting groundwater rise in historical centres of Eastern Siberian cities

The purpose of the research work is to develop a procedure for on-line prediction of the groundwater hydrodynamic mode change caused by the barrage effect of deep foundation structure construction. The main method used is the development of an analytical model as a result of variant solutions of the Laplace equation. The solutions have been elaborated in the course of studies conducted in historical centers of Irkutsk and other cities of Eastern Siberia. As a result, diagrams predicting the formation depth of groundwater level have been created, and the territories have been assessed according to their flooding conditions. An analytical model has been developed for backwater prediction. The model is rather simple, universal and can be applied for predictive calculations on the territories of historical cities located in similar geological and hydrogeological conditions. The available material analyzed, it is concluded that preliminary vertical planning of the territory, correct approach to foundation type selection as well as seasonal rise of underground water play a significant role in the formation of a new headwater elevation.

Foundations, Design, and Dynamic Performance of Wind Turbines: Overview and Challenges in Sudan

Sudan is one of the developing countries that suffers from a lack of electricity, where the national electrification rate is estimated at 38.5%. In order to solve this problem, it is possible to use renewable energy sources such as wind energy. Beside many aspects to be considered at the design of wind turbine foundations, more attention should be given to the geotechnical part. There are many types of foundations for wind turbines. The foundation must satisfy two design criteria: 1) It should be safe against bearing failure in soils under design loads and settlements during the life of the structure must not cause structural damage; 2) In addition to static loads, wind turbine foundations loads are extremely eccentrically and the loading is usually highly dynamic. Therefore, the selection of foundation type should consider these two criteria taking into account the nature and magnitude of these loads. This paper presents a review of different types of wind turbine foundations of focusing on on-shore wind turbine foundation types and the dynamic response of wind turbine. The paper also demonstrate experimentally the dynamic response of the wind turbines using wind tunnel facility test on a scaled model.

PEMILIHAN FONDASI CSTR UNTUK PRODUKSI BIOGAS DARI POME DALAM RANGKA MENINGKATKAN PENGEMBANGAN ENERGI TERBARUKAN

Renewable energy development for power generation is in line with the government's program toincrease the share of renewable energy in the national energy mix which is relatively small at themoment. BPPT, collaborating with PTPN 5 in the Insinas Flagship program, built a pilot plant for biogasproduction from Palm Oil Mill Effluent (POME) with a capacity of 700 kW. The reactor used in this pilotproject is a Continuous Stirred Tank Reactor (CSTR) which is the most important operating unit forproducing biogas from POME. Therefore, the selection of the CSTR foundation is crucial since themain process occurs in the reactor. The scope of this activity is to realize the final design into theconstruction of a CSTR pilot plant. Several types of foundations were studied, starting from shallowfoundation type such as tread foundation, deep foundation, until combining shallow foundation typewith deep foundation type. The evaluation of existing data and design review indicates that the use ofMat Foundation is not suitable due to soil condition at a depth of 0–5m which is in the form of sandyloam soil with an NSPT value of less than 20. The selection of Piles is based on the calculations usingtotal vertical load of 3035,37 ton and total horizontal load of 542,57 tons. Considering the availability ofmaterials and time concern, the recommended foundation type is pile with a diameter of 600 mm typeB and a length of 12 m.

Experimental and Numerical Study for Analyzing Applicability of Helical Piles

A helical pile is a foundation type that can be constructed to improve the bearing capacity and pullout resistance using a spiral plate affixed to the central shaft of the pile. In the past, piles were applied in formulaic shapes, but based on recent developments of threaded joints, the specifications of a helical pile can be applied depending on the site conditions. In this study, model tests and numerical modeling were performed to analyze the bearing capacity and pullout resistance based on the number, size, and position of the helix, which were the main factors of the helical pile. The bearing capacity and pullout resistance improved as the number and diameter of the helix increased. When the helix was installed near the bottom of the pile, the helical pile showed an excellent performance. In addition, by analyzing the ratio of the increase in the bearing capacity according to the area ratio of the helix as a part of the economic analysis, it is essential to consider the installation position of the helix. Based on the analysis results, it was shown that the helical pile could be improved.

Asymmetric Large Deformation Superharmonic and Subharmonic Resonances of Spiral Stiffened Imperfect FG Cylindrical Shells Resting on Generalized Nonlinear Viscoelastic Foundations

This paper is devoted to superharmonic and subharmonic behavior investigation of imperfect functionally graded (FG) cylindrical shells with external FG spiral stiffeners under large amplitude excitations. The structure is embedded within a generalized nonlinear viscoelastic foundation, which is composed of a two-parameter Winkler–Pasternak foundation augmented by a Kelvin–Voigt viscoelastic model with a nonlinear cubic stiffness, to account for the vibration hardening/softening phenomena and damping considerations. The von Kármán strain-displacement kinematic nonlinearity is employed in the constitutive laws of the shell and stiffeners. The external spiral stiffeners of the cylindrical shell are modeled according to the smeared stiffener technique. The coupled governing equations are solved by using Galerkin’s method in conjunction with the stress function concept. The multiple scales method is utilized to detect the subharmonic and superharmonic resonances and the frequency–amplitude relations of the 1/3 and 1/2 subharmonic and 3/1 and 2/1 superharmonic resonances of the system. Finally, the influences of the stiffeners helical angles, foundation type, coefficient of the nonlinear elastic foundation, material distribution, and excitation amplitude on the system resonances are investigated comprehensively.

Sustainable Risk Assessment through the Analysis of Financial Losses from Third-Party Damage in Bridge Construction

Due to the recent introduction of innovative construction methods and technologies, construction projects increasingly require sustainability in their high degrees of specialization and complex work processes. This is due to a wide variety of new risk factors associated with construction projects that can lead to extensive and severe damage. When an accident occurs during a construction project, it can cause material, property, or bodily damage not only within the actual construction site but also outside, affecting third parties. This study analyzed the record of such third-party damage and the subsequent financial losses in bridge construction management, to identify the objective and quantified relationship of risk indicators related to the damage and losses. In order to assess the actual losses in construction projects, we adopted the loss claim payout data as recorded and provided by a major Korean insurance company, and conducted a multiple regression analysis to identify the loss indicators and to develop a loss estimation model. In this study, the analysis of the data indicated that the superstructure type, the foundation type, floods, and company ranking by the amount of the contract were the four statistically significant risk indicators that affected financial losses from third-party damage, among the nine variables used as independent variables, which included the superstructure type, foundation type, superstructure construction method, maximum span length, floods, typhoons, total construction cost, total construction period, and company ranking. As this study focused on identifying the risk factors and producing a loss assessment model quantified in numerical values, the results provide important references for assessing and minimizing the risks to third parties and the consequential financial losses in bridge construction, while promoting sustainability objectives.

Using InSAR settlement data in a levee strengthening project for building settlement risk assessment

For the levee strengthening project Krachtige IJsseldijken Krimpenerwaard (KIJK) a study has been done to examine all buildings along 10 km of levee. These buildings are an important factor in the design stage, because of its sensitivity to deformations due to the natural compaction of the soft deposits (creep) and the potential effects of the levee strengthening. This paper covers the quantification of building settlement due to natural subsidence using InSAR. Research is performed in the city archives to establish the characteristics of the buildings, such as the foundation type. Although the city archive is well organised, it is not complete. The building data density is substantially improved using InSAR information. This enhanced data set is a key factor in establishing an consistent assessment of the risk of damage for the different levee strengthening alternatives.

Static and dynamic analyses of auxetic hybrid FRC/CNTRC laminated plates

In this work, a hybrid laminated plate is developed by changing ply orientations and stacking sequences. The hybrid laminated plate is composed of carbon nanotube reinforced composite and fiber reinforced composite layers. Negative Poisson’s ratio (NPR) is obtained for the case of [22F/(22C/−22C)3T/−22F] laminate. A theoretical laminated model considering geometric nonlinearity and shear deformation is presented. Based on a two-step perturbation method, the solutions of the motion equations are obtained to capture the nonlinear frequencies and load–deflection curves. On this basis, the fourth-order Runge–Kutta method is used to obtain the dynamic response of hybrid laminated plates. The presented model is verified by comparing the results obtained analytically and numerically. Several factors such as loading and distribution of carbon nanotubes (CNTs), and foundation type are considered in parametric study. Numerical results indicate that the thermal-mechanical behavior of hybrid laminated plates significantly improved by properly adjusting the CNT distribution. In addition, the results reveal that changes in temperature and foundation stiffness have pronounced influence on the nonlinear vibration characteristics of hybrid laminate plates with NPR as compared to those with positive Poisson’s ratio.