保定市防撞墙模具厂

桥梁防撞墙施工质量保障措施

Construction quality guarantee measures for bridge anticollision wall

引言

Introduction

防撞墙是桥梁的一种安全防护设施，由于防撞墙位于桥面系，处于桥梁最直观的位置，因而对其几何尺寸、表面光洁度、平整度等各项质量指标要求比较高。但防撞墙下部蹄形部位呈特殊的反弧形，在施工浇筑过程中蹄部前侧面气泡极难排出，拆模后往往出现较为密集的大小气泡，同时因在安装后的悬空板上现浇，给立模带来很大的难度，模板的接缝部位和底部常常由于漏浆出现蜂窝麻面等表面缺陷，这些也一直困扰着施工和监理人员。结合工程实际，本文对防撞墙的质量控制进行浅要分析。

The anticollision wall is a kind of safety protection facility for the bridge. As the collision wall is located in the bridge deck system, it is in the most intuitive position of the bridge, so its geometric size, surface smoothness and flatness are higher. However, there is a special reverse arc in the hoof shape part of the lower part of the anticollision wall. In the course of construction, the air bubbles in the front side of the hoofs are very difficult to expel. The more dense size bubbles often appear after the dismantling. At the same time, it is difficult for the vertical die to be poured on the suspended board after installation. The joints and the bottom of the template are often caused by the leakage of the slurry. Surface defects such as honeycomb, hemp and so on have also plagued construction and supervision personnel. Combined with the engineering practice, this paper analyzes the quality control of the anti-collision wall.

1 模板的安装

The installation of the 1 template

用于防撞墙的模板不宜采用小块组合式钢模板，而应采用大块钢模板。这是因为模板越小， 接缝越多，外观越差，而且接缝处表面不易平整，也易出现漏浆现象。控制钢筋保护层厚度 可使用小石块来填隔钢筋，不宜采用混凝土垫块，以免在拆模后墙体表面出现一块块难看的斑痕，立模时，在防撞墙侧模的顶部与底部分别安装一根用槽钢制作的横带螺丝杆固定。然后，在两侧的槽钢上均匀地安装几根钢支撑杆，使模板的整体得到固定。

It is not suitable to use small combined steel formwork instead of large steel formwork. This is because the smaller the template, the more joints, the worse the appearance, and the surface of the joint is not easy to flatten. The thickness of the reinforcement protection layer can be used to fill the steel bar with small stones. It is not suitable for the use of concrete padding blocks so as to avoid a unseen spot on the surface of the wall. When the mold is built, a screwdriver made of a channel steel is fixed at the top and bottom of the side die of the anti collision wall respectively. Then, several steel braces are evenly installed on the sides of the channel steel, so that the overall formwork is fixed.

2 混凝土质量控制

2 concrete quality control

由于防撞墙底宽上窄，其内部的钢筋布置较密，浇注混凝土施工时不利于排除气泡，所以对混凝土的和易性有较高的要求。

Because the bottom width of the collision wall is narrow, the interior of the steel bar is denser, it is not conducive to the exclusion of air bubbles in the construction of concrete, so it has high requirements for the workability of concrete.

在施工中，为了使混凝土的和易性更好，需要对集料的级配进行认真设计和调整，使其达到 最佳的级配曲线，可采用适当增加水泥用量及适当提高砂率的方法来处理，正常情况可将砂 率提高2%～3%，但砂率不能太大，含砂量过多，会使混凝土中的气泡难以上升逸出。在拌和 混凝土时，要注意拌和时间适当。拌和时间过长，会降低混凝土的和易性；而拌和时间太短 ，又不能得到匀质的混凝土，且会降低混凝土的强度。

In the construction, in order to make the concrete and easy to be better, it is necessary to carefully design and adjust the aggregate gradation so that it can reach the best grading curve. It can be treated by proper increase of cement content and proper sand rate. The sand rate can be increased by 2% to 3% in normal conditions, but the sand rate can not be too large and sand content is over. Many will cause the bubbles in concrete to rise and escape. When mixing concrete, pay attention to proper mixing time. Mixing time is too long, which will reduce the workability of concrete, and mixing time is too short to get homogeneous concrete, and it will reduce the strength of concrete.

3 混凝土的浇筑与振捣

3 concrete pouring and vibration

防撞墙混凝土坍落度控制在14±2cm，混凝土采用罐车运输，罐车驶至桥下后，采用龙门吊配合吊斗方式入模，混凝土到现场后先检测塌落度及含气量，符合要求后方可施工。防撞墙混凝土采用分层法进行浇注，每层浇筑厚度不得超过300mm。下料时不得在一个地方集中下料，防止形成起伏不定的界面。浇筑到护栏的倒角位置应暂时停止下灰，待该范围振捣完成后再继续浇筑。分层浇筑间隔时间应不大于混凝土的初凝时间。振捣棒应插入下层50～100㎜,振捣棒与侧模应保持50～100㎜的距离，严禁振捣棒直接接触模板。每一次振捣必须振捣至混凝土停止下沉，不再冒气泡，表面呈现平坦、泛浆时方可提出振捣棒。

The concrete slump of the anticollision wall is controlled in 14 + 2cm. The concrete is transported by tank car. After the tank car is driven to the bridge, the gantry crane is used to enter the mould with the way of the crane. After the concrete goes to the site, the collapse degree and gas content are detected first, which can be constructed in the rear. The anti-collision wall concrete is poured by layered method, and the thickness of each layer can not exceed 300mm. When cutting, it is not allowed to concentrate in one place and prevent the formation of fluctuating interfaces. The position of the chamfering poured into the guardrail shall be temporarily suspended until the vibration is completed. The interval time of layered pouring should not be greater than the initial setting time of concrete. The vibrating bar should be inserted into the lower level 50~100, and the vibrator and the side die should be kept at a distance of 50~100. Each vibration must be vibrated to the concrete to stop sinking, no bubbles will be bubbled up, and the surface will be flat and wide.

护栏顶面混凝土分三次进行收面作业。混凝土浇注后2～3小时采用木抹进行第一次收面，5～6小时用铁模进行第二次收面，混凝土初凝前完成第三次收面作业，收面时重点控制混凝土表面平整度，确保护栏顶面平整，线形顺畅。

The concrete on the top surface of the guardrail is divided into three operations. After 2~3 hours of concrete pouring, the first face is used by wood wipes, second faces are made with iron mould for 5~6 hours, and third finishing operations are completed before the concrete initial setting. The surface evenness of concrete is controlled emphatically when the face is collected, so that the top surface of the guardrail is smooth and the line is smooth.

4 养护与拆模

4 maintenance and dismantling

撞墙模板拆除时间根据气温实行动态调整，目前模板拆除时间控制在混凝土浇注完成后24小时左右，模板拆除时现场设专人指挥，防止拆模过程损坏混凝土边角。

The dismantling time of the wall template is adjusted dynamically according to the temperature. At present, the removal time of the template is controlled about 24 hours after the completion of the concrete pouring, and the site is commanded by a special person when the template is dismantled to prevent the process of breaking the concrete side angle.

养护：防撞墙混凝土浇注完成后，采用塑料薄膜对混凝土顶面进行覆盖湿水养护，防止气温过高混凝土表面发生裂缝，模板拆除后，及时用土工布对防撞墙混凝土进行包裹，并洒水养护，养护时间不小于7d，为确保养护质量，桥面专门设置二道自来水管用于养护供水。

Maintenance: after the concrete pouring is completed, the concrete top surface is covered with wet water with plastic film to prevent the cracks on the surface of high temperature concrete. After the formwork is dismantled, the concrete is wrapped in time with the geotextile, and the maintenance time is not less than 7d, in order to ensure the quality of the maintenance. The surface is specially equipped with two self running water pipes to maintain water supply.

5 防撞墙施工出现质量问题及改进措施

Quality problems and improvement measures in the construction of 5 collision proof wall

5.1防撞墙顶部圆弧部分混凝土缺边掉角的改进措施

5.1 improvement measures for concrete missing corner of the top part of the anti-collision wall

由于防撞墙顶部圆弧位置混凝土施工中不易振捣密实，模板拆除后，圆弧位置混凝土成型质量较差，混凝土光洁度不良，缺边掉角现象较多，针对这种现象，项目部采用了第二次收面过程中使用小平板振捣器二次复振的方法，有效改善了防撞墙顶部混凝土的密实度，显著提高了防撞墙顶部圆弧位置混凝土的外观质量。

Because the circular arc position of the top of the anticollision wall is not easy to vibrate and compactness in the concrete construction, after the formwork is dismantled, the forming quality of the circular arc position concrete is poor, the concrete finish is bad, and the edge missing angle is many. In view of this phenomenon, the project department adopts the method of using the Ohira Izhen rammer to recover two times during the second times of the process. The density of the concrete at the top of the anti-collision wall is effectively improved, and the appearance quality of the concrete at the top arc position of the anti-collision wall is significantly improved.

5.2防撞墙混凝土裂缝的改进措施

Improvement measures of concrete crack in 5.2 collision proof wall

首件防撞墙施工后，防撞墙混凝土顶面出现了较多的微小裂缝现象，经过分析研究，项目部对防撞墙及波形护栏基础分三次进行收面，混凝土初凝前使用铁摸进行最后一遍压光收面处理，通过收面愈合之前混凝土表层产生的塑性裂缝，收面完成后，混凝土顶面及时覆盖一层塑料薄膜，并对混凝土顶面湿水养护，波型护栏基础混凝土收面时，因工作量较大，收面时间较长，现场在波型护栏基础混凝土顶面以上40cm高度搭设了一道土工布，以减小波型护栏基础混凝土表面温度及风速，减

After the first anticollision wall construction, there are many small cracks in the concrete top surface of the anticollision wall. After analysis and research, the project department carries out three faces to the anti-collision wall and the foundation of the wave guardrail. Before the concrete initial coagulation, the iron touch is used to handle the final surface of the surface of the concrete surface, which is produced by the surface of the concrete surface before the surface is healed. When the surface of the concrete top surface is covered by a plastic film on the top surface of the concrete, and the concrete top surface is cured by the concrete top surface, when the concrete top surface is covered with wet water, the work load is large and the time of the face is long. The site is set up a geotextile for the 40cm height above the concrete top surface of the wave type guardrail to reduce the wave type protection. The surface temperature and wind speed of the concrete surface of the column is reduced.