Investigating significance of various parameters affecting capacity of core drilled columns for safe core extraction

The objective of this article is to identify and analyze the main pathological manifestations in bridges in the Chapare - Bolivia region, an area characterized by high humidity and constant rainfall throughout the year. The methodology consisted of the selection of five bridges that showed evident signs of deterioration, in which a visual inspection was carried out and, subsequently, different tests: sclerometer, carbonation depth, penetration of chlorides and core extraction. All the bridges present advanced states of deterioration; highlighting corrosion as the main problem, generating detachment of the concrete and risk of collapse. Although the concrete has a compression strength greater than 30 MPa, the existing carbonation process and the different problems encountered compromises it. It is necessary that the entities in charge provide inspection and maintenance programs according to the environmental and structural characteristics of each bridge.

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Dynamite 2.0: New Features Based on UnSAT-Core Extraction to Improve Verification of Software Requirements

Lecture Notes in Computer Science - Theoretical Aspects of Computing – ICTAC 2010 ◽

10.1007/978-3-642-14808-8_19 ◽

2010 ◽

pp. 275-289 ◽

Cited By ~ 2

Author(s):

Mariano M. Moscato ◽

Carlos G. López Pombo ◽

Marcelo F. Frias

Keyword(s):

Software Requirements ◽

Core Extraction

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PROPOSAL OF EVALUATION METHOD FOR RESIDUAL AXIAL FORCE OF CORRODED HIGH-STRENGTH BOLTS

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2015.85 ◽

2015 ◽

Vol 2 (1) ◽

Author(s):

M. Tai ◽

T. Shimozato ◽

Y. Arizumi ◽

S. Yamashita ◽

T. Yabuki

Keyword(s):

Axial Force ◽

Strain Gauge ◽

Evaluation Method ◽

Force Measurement ◽

High Strength ◽

Fe Analysis ◽

Thickness Reduction ◽

Steel Bridge ◽

Core Extraction ◽

Measurement Of Thickness

In this research an evaluation method for the residual axial force of corroded high-strength bolts was investigated. Corroded high-strength bolts cut from a steel bridge were used for the measurement of thickness reduction and residual axial force. For the residual axial force measurement, a strain-gauge method with a core extraction was applied. An FE analysis examined the effect of the corroded shape of high-strength bolts on the residual axial force. The results reveal that the effect of corroded shapes on the residual axial force can be considered by using the thickness reduction amount near the washer for nut and bolt head. A proposed evaluation method based on the summation of thickness reduction can estimate the residual axial force of corroded high-strength bolts approximately.

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The investigation and proposed rehabilitation of the Tsing Yi South Bridge, Hong Kong

Canadian Journal of Civil Engineering ◽

10.1139/l88-026 ◽

1988 ◽

Vol 15 (2) ◽

pp. 190-198

Author(s):

A. S. Beard ◽

H. S. S. Tung

Keyword(s):

Prestressed Concrete ◽

Load Testing ◽

Concrete Core ◽

Box Girder ◽

Expansion Joints ◽

Radiographic Inspection ◽

Core Extraction ◽

Long Term Performance ◽

Term Performance

The Tsing Yi South Bridge was constructed in the early 1970s to provide access between Tsing Yi Island and the mainland at Kwai Chung. It has a prestressed concrete box girder superstructure consisting of five independent units which are monolithic with their piers and have expansion joints at the mid-span shear hinges and the abutments. During routine maintenance it was found that the superstructure cantilevers were deflecting excessively, and consequently a thorough inspection and appraisal were commissioned. These included a complete visual inspection, concrete core extraction, radiographic inspection of prestressing tendons and a programme of load testing. The bridge was also reanalyzed to check its long-term performance. Subsequently, a rehabilitation scheme was designed to recover part of the deflection. This involved the introduction of additional prestress near the box girder's top flange. Key words: prestressed concrete, structural assessment, creep, shrinkage, radiographic inspection, rehabilitation, external prestressing.

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Key Component Design of Environment-Friendly Jujube Takes Core Machine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.734-737.2761 ◽

2013 ◽

Vol 734-737 ◽

pp. 2761-2764

Author(s):

Quan Shan ◽

Yan Chen

Keyword(s):

Structure Calculation ◽

Environment Protection ◽

Kinematics Analysis ◽

Detailed Structure ◽

Extraction Technology ◽

Environment Friendly ◽

Component Design ◽

Core Extraction ◽

Design Result ◽

New Machine

Environment-friendly wild jujube takes core machine is proposed in the current serious water pollution situation. At the time of take jujube core, the jujube core and jujube meat is difficult to separate. So, it needs to use a lot of water to flush the jujube meat. The wastewater, which contains jujube meat, brings great pollution to the environment. To solve this problem, the existing jujube core extraction technology is analyses firstly. Then a new project of jujube take core machine is proposed in this paper. This new project can separate the jujube core and the jujube meat in the same machine. The detailed structure calculation and kinematics analysis of the new machine key components, such as the broken device and the separate device, were done on the computer. Finally, according to the design result, using the software Pro/ENGINEER, the prototype machine was designed and manufactured, then test lots of times. The experiment proved that the machine can effectively reduce water consumption and the volume of sewage to achieve the purpose of environment protection.

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Investigation of construction material quality and workmanship defects of RC buildings collapsed and severely damaged in the 6.8 Mw Sivrice, Elazığ, Turkey earthquake, January 2020

Bulletin of the New Zealand Society for Earthquake Engineering ◽

10.5459/bnzsee.54.3.184-196 ◽

2021 ◽

Vol 54 (3) ◽

pp. 184-196

Author(s):

Murat Bikçe ◽

M. Musab Erdem

Keyword(s):

Sampling Method ◽

Construction Material ◽

Reinforcing Bars ◽

Judicial Process ◽

Adverse Conditions ◽

Emotional Sensitivity ◽

Earthquake Zone ◽

Core Extraction

In the Sivrice, Elazığ, Turkey earthquake on January 24, 2020, 41 people lost their lives, more than 1600 people were injured, 672 buildings collapsed, and around 12600 buildings were severely damaged due to poor construction quality. After such devastating earthquakes, damage assessment and forensic investigations are normally carried out quickly for a judicial process, and material qualities are revealed. However, emotional sensitivity of the victims in the earthquake affected zone and disruptions in key lifeline services such as transportation, electricity supply often make these processes difficult. After the Elazığ earthquake, along with the conventional in-situ core sampling method, concrete pieces were collected from columns of collapsed and severely damaged buildings and transported out of the earthquake zone to overcome these adverse conditions. Unlike in the conventional method where the whole sampling process is carried out in the earthquake zone, the core extraction from the transported concrete pieces was carried out outside the earthquake-affected area. The extracted concrete samples were checked for compliance with the prevailing material standards. Moreover, multiple reinforcing bars of various diameters were also extracted and tested to check their compliance with the standards. Besides, the results of examination of the quality of materials and workmanship used in the construction are also discussed, along with the precautions required to minimize fatalities and damage from similar buildings.

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Abstract Cores in Implicit Hitting Set MaxSat Solving (Extended Abstract)

Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence ◽

10.24963/ijcai.2021/643 ◽

2021 ◽

Author(s):

Jeremias Berg ◽

Fahiem Bacchus ◽

Alex Poole

Keyword(s):

Linear Programming ◽

Optimization Problems ◽

State Of The Art ◽

Empirical Evaluation ◽

Boolean Satisfiability ◽

Compact Representation ◽

Maximum Satisfiability ◽

Hitting Set ◽

Combinatorial Optimization Problems ◽

Core Extraction

Maximum satisfiability (MaxSat) solving is an active area of research motivated by numerous successful applications to solving NP-hard combinatorial optimization problems. One of the most successful approaches for solving MaxSat instances from real world domains are the so called implicit hitting set (IHS) solvers. IHS solvers decouple MaxSat solving into separate core-extraction (i.e. reasoning) and optimization steps which are tackled by a Boolean satisfiability (SAT) and an integer linear programming (IP) solver, respectively. While the approach shows state-of-the-art performance on many industrial instances, it is known that there exists instances on which IHS solvers need to extract an exponential number of cores before terminating. Motivated by the simplest of these problematic instances, we propose abstract cores, a compact representation for a potentially exponential number of regular cores. We demonstrate how to incorporate abstract core reasoning into the IHS algorithm and report on an empirical evaluation demonstrating, that including abstract cores into a state-of-the-art IHS solver improves its performance enough to surpass the best performing solvers of the 2019 MaxSat Evaluation.

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