Dynamic Distribution-Sensitive Point Location

We propose a dynamic data structure for the distribution-sensitive point location problem in the plane. Suppose that there is a fixed query distribution within a convex subdivision S , and we are given an oracle that can return in O (1) time the probability of a query point falling into a polygonal region of constant complexity. We can maintain S such that each query is answered in O opt (S) ) expected time, where opt ( S ) is the expected time of the best linear decision tree for answering point location queries in S . The space and construction time are O(n log 2 n ), where n is the number of vertices of S . An update of S as a mixed sequence of k edge insertions and deletions takes O(k log 4 n) amortized time. As a corollary, the randomized incremental construction of the Voronoi diagram of n sites can be performed in O(n log 4 n ) expected time so that, during the incremental construction, a nearest neighbor query at any time can be answered optimally with respect to the intermediate Voronoi diagram at that time.

Bubbled Roller Compacted Concrete Dam: an idea of a hollow dam

Roller compacted concrete is widely known for its relatively low cost and short construction time. RCC gravity dams require high foundation (rock) bearing capacity. Research has been carried out which proposes to rationalise the amount of material in the dam by creating inner voids, in the shape of bubbles. As a key requirement, the introduced bubbles should not affect the dam stability and safety. The bubbles will reduce the self-weight of the dam and minimise the required rock bearing capacity. A system of pipes connecting the bubbles ensures drainage of the bubbles. The proposed dam would save about 12% of the required concrete volume. Different construction methods were studied and the best alternative is the use of precast hollow boxes. This decreases RCC placement in the dam by 32.5%. The objective is to speed the construction process and minimise the risk of the heat of hydration.

Seismic Behaviour of Rc Building Located in Erbil, Iraq and Strengthening by Using Steel Frame Sections Precast Bolt-Connected Steel-Plate Reinforced Concrete

This paper present outside strengthening with precast substructures, is a relatively new retrofitting approach that has recently attracted the attention of researchers. Outside strengthening with precast substructure, in contrast to member-level strengthening technologies (e.g., FRP strengthening, enlarging member section areas, and replacing rebars), is a structure-system reinforcement method that integrates the substructure and the original structure, improves overall seismic performance, and changes the deformation mode of the entire structure. The seismic capability of the exterior strengthening with precast bolt-connected steel-plate reinforced concrete is critically evaluated in this paper (PBSPC) Case studies are used to demonstrate the working principles, numerical methodologies, and design approaches. The simulation results were similar with prior studies, demonstrating that the numerical model was effective. The use of building steel representations reduces construction time, increases efficiency, and lowers costs. The goal of this technology is to lower the seismic displacement demand of nonductile. Current RC structures have steel frames connecting to the building floors. These frameworks run parallel to the structure of the building. Ganjan Life City, a building in Erbil, Iraq, is being used as a case study. The ISC 2017 and ASCE 7-10 earthquake codes were used to evaluate the building’s seismic performance before and after the reinforcement. The analysis’ findings suggest that the recommended technique is correct.

Solution of Bullet Proof Wooden Frame Construction Panel with a Built-In Air Duct

The growing terrorism threats across the world play an important role in the design of civil buildings and living areas. The safety of personnel is a top priority in unclassified buildings, especially military buildings. However indoor air quality and thermal comfort has a direct impact on personal productivity and ability to concentrate on duties and affect the decision making in stress conditions. The use of wooden structures is becoming more common in the building construction, and application of wooden frame structures for the construction of new buildings as well as for retrofitting the existing buildings. Prefabricated wooded frame construction perfectly fits need of unclassified buildings, allowing significant reduction of construction time and integration of various active and passive elements, such as a fresh air supply duct. Within the scope of this paper a 12 mm thick ballistic panel made of aramid was tested. Ballistic panel, thermal conductivity, and fire resistance of wooded construction panel with embedded air duct were analyzed for the various modelled exterior wall solutions. The main advantage of the proposed technology is fast and qualitative modular construction of unclassified buildings, providing all modern requirements not only for safety, but also for the energy efficiency and indoor air quality. It was found that bullet proof aramid panels do not reduce overall fire safety in comparison to traditional construction materials. However embedded outdoor air supply ducts significantly reduces construction heat transfer coefficient.

Basic Experimental Evaluation of Fresh and Hardened Properties of Mortar Using Additive Manufacturing

Recently, the three-dimensional concrete printing (3DCP) method has been garnering considerable interest owing to its ability to significantly reduce the construction time. In this study, 3D printing or additive manufacturing was applied to mortar using a small gantry type equipment and the performance of the method was evaluated. The mixture proportioning for good mortar printing and deposition was derived. The parameters of printability, buildability, compressive strength, flexural tensile strength, and anti-washout were considered for the performance evaluation. The results showed good printability with a constant width and no surface defects. In the buildability test, the rate of yield stress development increased, and the rate of change in the layer height decreased as the interlayer time interval increased during underwater printing. The flexural tensile strength of the specimen cast into the mold was lower than that of the specimen extracted from the additive parts owing to the longitudinal confinement during printing. The compressive strength in the lateral direction was slightly higher than that in the perpendicular direction, whereas the compressive strength of the specimen extracted from the part printed underwater was higher than that of the specimen cast into the mold.

Laboratory And Field Tests On A Prefabricated Steel-Bar Mesh-Panel System For Continuously-Reinforced-Concrete Pavement (CRCP)

The decline in the number of persons of working age is a social problem in Japan. This is a particularly serious concern for workers in the construction field; construction systems should be considered for productivity improvements. Prefabrication systems are an effective method for shortening construction cycles and times. In fact, various precast concrete members have been employed to realize more rapid construction and improvements in quality. Using precast concrete members is difficult because jointless roads are preferable for highway pavement. Continuously reinforced concrete pavement (CRCP), which has the advantages of concrete jointless construction and high ductility, is a suitable method for highway road construction. Typical Japanese highways built with CRCP reduce the amount of horizontal cracking by arranging transverse rebars at an angle of 60° to the main rebars. Note that rebar placement and bonding in conventional CRCP are troublesome and labor intensive owing to the long construction time required. We have developed prefabricated steel bar meshes for CRCP and can report some benefits relating to their practical application. To examine the fundamental properties of mesh panels, we conducted a laboratory experiment and a simulated field test. The primary concern of welded rebars are failures induced by cyclic loading. A flexural fatigue loading test using CRCP models was conducted. In addition, a comparative survey on conventional and prefabrication systems was performed in the simulated field test to quantify the constructability of CRCP and to observe the extent of cracking in concrete. This paper reports on our experimental investigation.

Synanthropic spiders’ diversity (Arachnida, Araneae) in the urban zone of Morelia citiy, Michoacan, Mexico. How much does the time of construction of the houses influence?

Spiders have been used to evaluate changes in systems by anthropization effect, some species showing sensitivity to gradual and drastic changes such as urbanization, and other species have been documented as tolerant to this effect. The goal of this work was to describe the change in the spider community in relation to the age of buildings. at the west of Morelia, Michoacán, Mexico. Three categories of construction time and the neighboring vegetation as the pre-urbanization environment were used for comparison. Using direct capture, pit-fall traps and beating nets, 3,619 spiders were collected, and 3,219 (315 males, 630 females and 2,274 immatures) were used for the analysis after removal juveniles that was not possible to identify. A total of 28 families, 93 genera, 47 species and 55 morphospecies were identified. This represents the greatest richness and abundance recorded in urban environments of the country. It describes changes in alpha diversity from colonization in recent constructions to those built 17 years ago. I t was observed that abundance, richness, and diversity decrease with the age of a building, but with high equitability in every age of construction. The age of a building is an important factor for the process of succession in urban environments.

Lean Construction Concept Used to Develop Infrastructure Facilities for Tourism Clusters

The relevance of the article is conditioned on tourist infrastructure problems and underdevelopment when creating and developing territorial clusters, for which there is not enough research materials in the context of tourism cluster facilities construction, despite the fact that the issues of lean construction (LC) are widely covered. Based on the relevance, the main hypothesis of the study was determined. It consists of the fact that the use of lean construction can increase the efficiency of construction megaprojects in the field of tourism clusters. The objective of this study is to develop a mechanism for the development of tourism clusters based on the lean construction concept that will be aimed at increasing the efficiency of construction projects taking into account the accumulated world experience. Within the framework of the tasks set, the analysis of the lean construction methodological base was carried out, methodological recommendations aimed at increasing the efficiency of construction megaprojects of tourism clusters based on the lean construction concept were developed, a model for the implementation of lean construction in infrastructure projects of tourism clusters, as well as a checklist of the analysis technology were elaborated. The proposed methodological approach to the implementation of tourism cluster megaprojects based on the lean construction concept is the basis for organizing and planning development activities at the tactical and operational levels. To assess the effectiveness of lean construction tool introduction to implement infrastructure projects of tourism clusters, a comparative analysis was carried out and the construction time and lifecycle cost of a typical guest house were calculated without taking into account the lean construction methodology and after its introduction. The results obtained, namely, the duration of the project and costs at life cycle stages made it possible to conclude that the proposed methodological approach is effective.

Small Pilot Tunnel Advance and Step Reverse Expansion in Super-Large-Section Tunnel Excavation

Collapse of the vault and numerous other safety accidents often occur during the construction process of large-section tunnels. The utilization of a small pilot tunnel and a step reverse expansion construction methodology is proposed based on conventional construction methods to explore safe construction technology. First, a theoretical analysis combined with on-site monitoring parameters was conducted. It showed that the maximum displacement of the tunnel surrounding rock was 0.027 m during the elastic stage and increased to 0.031 m during the strength limit stage. The overall surrounding rock deformation does not have a noticeable impact on tunnel safety. A numerical simulation model of the small pilot tunnel advancement and step reverse expansion method was established. Simulation results showed that the first two excavation steps caused 89.6% of the total overlining strata subsidence, and the use of a small pilot tunnel advancement and step reverse expansion method can enhance the tunnel support. The tunnel surrounding rock was adequately stabilized after using this excavation method and provides the in-situ conditions for expanding the pilot tunnel to the large-section tunnel. The proposed method was adopted in an actual engineering project. It protected the subsequent construction of the main tunnel and decreased construction time, saving construction costs while ensuring safety, reducing construction risks, and improving production efficiency. This research can guide similar tunneling projects.

Step Change in Delivering High Fracture Wells by Eliminating Expandable Liner

This paper discusses the journey of finding alternate solution for having to run the Expandable Liners operations in the Fahud field which is already one of the most operationally challenging fields to drill in Petroleum Development Oman (PDO), due to the presence of a gas cap in highly fractured and depleted limestone formations with total losses and the need for dynamic annulus fill to maintain primary well control. In Fahud field, there is a highly reactive shale formation within reservoir limestone formation. Due to high likelihood of total losses, this shale formation caused bore hole instability challenges while drilling. And with more depletion took place, the challenges became more frequently to occurred. In 2001, expandable tubular liner was introduced to address these bore hole instability challenges while drilling highly reactive shale formation under total losses in the 8-1/2″ section. The use of expandable technology was sustained over the years in delivering all wells drilled to traverse this reactive shale column. Previously before 2001, wells used to have fat well design by installations of extra casing to cover the formations and problematic zones. Also, Fahud field was not depleted as it is now, and the problematic shale zone used to drill by normal conventional way without any issue using inhibition frilling fluid. Petroleum Development Oman (PDO) identified expandable liner as a preferred alternative to ‘Fat’ well design. The ‘Fat’ well design would have a large hole size through potential loss zones, resulting in unmanageable volumes of water being required. Expandable liber was fast-tracked - various technical options were considered by PDO with expandable liner technology being identified as the best solution to address the problem of the shale column. However, the deployment of expandable tubular liner technology supported to drill & deliver wells but also has its associated challenges incurring additional time and cost with reasonable installation and low operations success rate due to number of operational steps required prior and after the expandable liner. Adding to that, all the challenges associated with each step. The installation of the expandable liner required eight operational steps with multiple trips to under-ream, install and expand, cement, caliper log and drill through the liner which increased the probability of something going wrong due to mainly the challenging well profile and multiple operations steps. The expandable liners technology was required when the target formation was below the reactive shale interval. The team carried out a study of previous deployments with the intention of identifying well planning and operational contributors to the installation difficulties and operations failures, with a view of eliminating the need for installing the expandable liner and drilling the well to the desired landing point at designed section total depth. Most of the unsuccessful installation rates were observed to be prevalent in wells with high angle applications. The team also observed that the length of the hole interval below the reactive shale column contributed to the number of unsuccessful installation and operational failure rates recorded. The team evaluated the impact of reducing well inclination on the ability to deliver the hole section without installing the expandable liner. Subsequently the team developed an optimization plan which involved keeping all build activities above and below the problematic interval and holding tangent at less than 45° inclination while drilling across the problematic shale. In conclusion, in 2020 the team delivered six wells (90% of wells crossing reactive shale formation delivered) using the above described approach and traversed the historically highly reactive shale formation without installing expandable liners. This resulted in a 20% reduction in total well construction time and 17% reduction in total well delivery cost per well. In addition to the time and cost saving, with the new approach, described in this paper, less water needed to be pumped for dynamic fill. This allowed bringing the wells quicker to production, thus reducing oil deferment.