본시험은 경운(耕耘)이 불가능한 산지(山地)를 경운(耕耘)을 하지 않고 초지화(草地化) 할 수 있는 효과적인 방법(方法)을 구명(究明)할 목적으로 1983-1984년 사이에 수행되었다. 시험구의 처리로서는 제초제(除草劑)를 살포하지 않은 무처리구와 Glyphosate 및 Paraquat의 다른 양(量)을 목초파종(牧草播種) 30일, 445일 및 60일전에 살포하는 구를 두었다. 오차드그라스의 정착율(定着率)은 제초제의 영향을 받지 않았으나 라디노클로비의

The purpose of this study is to evaluate the vegetation recovery status of Mudeungsan National Park Jungmeorijae, Jeungsimsa district restoration site, and the Shimwon Valley ecological landscape restoration site in Jirisan National Park. Compared to the control plots, the Jungmeorijae restoration site was analyzed to have height growth of about 73.5%, the average species diversity index of about 75.2%. and the average similarity index was recovered to 7.75%. In the case of the restoration site in Jeungsimsa district, the height growth compared to the control plots was about 69.2%, the average species diversity index was about 55.0%. and the average similarity index was recovered to 25.65%. In the case of the Shimwon Valley ecological landscape restoration area, the height growth compared to the control plots was about 32.6%, the average species diversity index about 176.7%. and the average similarity index was recovered to 0.85%. The restoration site of the Jeungsimsa district was planted with relatively large trees during restoration work, and it took a relatively long time(20 years). Also, the site had less limiting factors due to the low elevation, allowing the degree of vegetation recovery to be higher than that of other sites.

This paper proposes a method to simultaneously estimate two degrees of freedom in wrist forces (extension - flexion, adduction - abduction) and one degree of freedom in grasping forces using Electromyography (EMG) signals of the forearms. To correlate the EMG signals with the forces, we applied a multi - layer perceptron(MLP), which is a machine learning method, and used the characteristics of the muscles constituting the forearm to generate learning data. Through the experiments, the similarity between the MLP target value and the estimated value was investigated by applying the coefficient of determination (R2) and root mean square error (RMSE) to evaluate the performance of the proposed method. As a result, the R2values with respect to the wrist flexionextension, adduction - abduction and grasping forces were 0.79, 0.73 and 0.78 and RMSE were 0.12, 0.17, 0.13 respectively.

The indoor thermal conductivity test, unfrozen water test, and freezing pressure test were conducted on soil mixed with waste vinyl aggregate (PE aggregate). Consequently, lower thermal conductivity, less unfrozen water, and lower freezing pressure resulted from higher PE aggregate mixing ratios. Furthermore, the plate loading test and frost penetration depth test were conducted on field model road with a sub-base of PE aggregate and crushed stone. As a result, the bearing capacity of the road mixed with 10% PE aggregate exceeded the requirement, whereas frost penetration depth was reduced by 39% compared to that of using crushed stone only.

In this study, CO2 reduction type quaternary component high fluidity concrete was produced with more than 80%r eduction in cement quantity to increase the use of industrial by product sand enhance construction performance, there by reducing CO2 emissions. Furthermore, theq uality properties, and CO2 reduction performance of this concrete were evaluated. As a result of the quality evaluation of quaternary component blended high fluidity concrete with CO₂reduction, the target performance could be achieved with a 80% or more reduction of cement quantity by mixing a large amount of industrial byproducts. The required performance level was obtained even though the flow, mechanics, and durability characteristics decreased a little compared to conventional mix.

Conventional approach for restraining additional lateral movement of bridge abutment is to decrease applied load by replacing rear ground with EPS block, ALC(autoclaved lightweight concrete), to increase soil resistance by applying tie-rod, geo-grid, permanent anchor, counterweight fill, and to increase lateral bearing capacity of soil by installing grouting, restraint pile. With properly restrained lateral movement of bridge abutment by applying those methods, the expansion joint and bridge bearing can be repaired after securing expansion joint gaps by cutting off concrete slabs and steel box girder. In this paper, the proposed approach for securing expansion joint gaps by restoring displaced bridge abutment to its original position with the use of hydraulic jacking device is discussed. By using hydraulic jacking device, cutting off concrete slabs and steel box girder is unnecessary.

This study suggests a PM interaction curve as a management element to prevent collapse of system supports. the FE analysis result show the element buckes when the element is beyond the PM curve. Since the system is able to resist a certain flexural strengths it is determined that the PM curve is suitable for a management element.

This study results the shear capacity of a wall depending on the postion and reinforcement of the equipment opening using finite element analysis. Analysis results show that when the openings are placed in the corner, the shear capacity was reduced than in the center. and reinforcing with a steel sleeve can compensate for the reduced strength

For reinforced soil slopes with anchors, additional slope reinforcement using anchors is highly difficult due to their interference with previously installed anchors. This case study presents the applicability of high pressure jet nail for the reinforcement of slopes where additional reinforcement is needed due to the loss of tensile force in the anchors.

Acceleration measurement is widely employed, because acceleration sensors generally have low noise and cost effective. To determine cable tension, FFT analysis of measured acceleration data is widely used. This study proposes a stay cable measurement system using acceleration data to determine the cable tension and vibration amplitude. A small light-weight wireless sensor is also proposed to increase the applicability.

농촌에서 발생하는 폐비닐(LDPE :Low Density Polyethylene)의 재활용율을 높이기 위해 폐비닐을 흙이 묻은 채로 180~200℃로 녹여 크기 19mm 되는 PE골재를 만들었다. 이 골재를 밀입도 아스팔트콘크리트 배합용 19mm 쇄석골재와 중량비로 0%, 2.5%, 5%, 10%, 15%씩 치환한 아스팔트 혼합물을 만들어 바인더 양 변화에 따른 마샬안정도시험을 실시하는 한편, 동결융해 후 인장강도시험, 동결융해 후 초음파속도시험을 실시하였다. (1) PE골재 혼합률별 마샬안정도시험 결과 : 모든 공시체에서 마샬안정도 최소기준을 만족하였고, PE골재 치환률이 높을수록 안정도가 급격히 커졌다. 흐름치는 PE골재를 치환한 모든 공시체에서 허용기준을 벗어났고, 혼합률이 높을수록 흐름치가 증가하여 소성변형에 다소 취약한 것으로 나타났다. 그러나 안정도와 흐름치를 동시에 고려했을 경우 PE골재를 혼합한 공시체의 안정도가 월등히 큰 것을 감안한다면 안정도 허용기준에 해당하는 소성변형은 크지 않을 것으로 판단되었다. (2) 동결융해 후의 인장강도 시험 결과 :쇄석만의 아스콘에 비해 PE골재 혼합 아스콘 공시체는 동결융해를 급격히 받은 후에도 더 큰 인장강도를 보였다. 단, PE골재를 5% 이상 섞었을 때는 PE골재 혼합율이 늘수록 약간씩 인장강도가 감소하는 경향을 보였다. (3) 동결융해 후 초음파속도 시험 결과: PE골재를 혼합한 아스콘을 도로에 포설 시 겨울철 동결융해의 반복으로 골재 내부의 공극이 감소(단열효과 감소)하는지 알아보기 위해 초음파속도를 측정한 결과 동결융해 반복 후에도 초음파속도는 감소하지 않았다. 즉, 현장에서 동결융해를 받아도 PE골재를 사용한 아스콘은 쇄석골재 사용시보다 단열효과가 큼을 알았다.

With the increasing use of pumping to place concrete, the development and refinement of the industry practice to ensure successful concrete pumping is becoming an important need for the concrete construction industry.

This paper summarizes the technical methods associated with concrete pumping and the development in concrete pumping that have been published in the technical literature and identifies future research needed for the industry to develop best practices for ensuring successful concrete pumping in the field.

Bridge decks are rapidly deteriorated by various environmental effects such as heavy vehicle and deicing salt, etc. For bridge owners in Korea, therefore, it is important to understand the defect characteristics and causes of deterioration of bridge decks as well as to predict the future need for bridge deck replacement based on proper deterioration models. Finding a solution to the problem, in this research, the site investigation for 76 domestic old bridges were undertaken and deterioration models of bridge decks were proposed by analysing service year-condition index relationships of more than 500 bridges.

Prevention methods for lateral movement of abutment include increasing the bearing capacity of foundation, improving the soft ground and reducing the external loads. These methods are usually adopted prior to the bridge construction. However, it is not easy for them to be applied to the bridge during common use. Because they are not only difficult to be constructed, but also potential causes of stability of the bridge. Instead, counterweight fill, grouting and permanent anchorage can be considered as alternatives when the lateral movement of abutment occurs. Among them, grouting has been adopted a lot recently. In this study, analysis is carried out to review the reinforcement effect of grouting method.

This study relates to a crack repair techniques in the concrete structure. In order to develop repair material containing self-healing agents, smart repair methods were investigated. For the micro cracks of less than 0.3 ㎜, new repair method of surface treatment was suggested by the simple crack repair stick. In case of over 0.3 ㎜ cracks, injection method using inorganic materials was suggested for drying shrinkage and water leakage.

This paper presents a study on the construction method of modular pier system using CFTs. Modular Pier System consist of various prefabricated modules and is constructed by assembling components. Research scop include development of standard modules for adjustable to various height, connection between modules, and test bed construction. For the evaluation of this systems’s performance, Many numerical and experimental studies were conducted. In this study, we develop rapid construction system for site application of modular pier.

In experimental results, the prediction equation for 28 day-strength of GGBF slag concrete could be produced through the linear regression analysis of early strength and 28 day-strength. In order to acquire the reliability, all mixture were repeated as 3 times and each mixture order was carried out by random sampling. The prediction equation for 28 day-strength of GGBF slag concrete by 1 day strength won the good reliability.