- 學位論文
混凝土用黏結式錨栓之ACI與EOTA性能評定與比對
Post-Installed Adhesive Anchors in concrete ACI and EOTA Assessment and Comparison.
本文將於2030/02/06開放下載。若您希望在開放下載時收到通知，可將文章加入收藏。
摘要
目前黏結式錨栓(化學錨栓)已廣泛應用於混凝土結構補強、連接或修正結構設計不足之用途，然有效應用化學錨栓於各項工程時，仍高度仰賴其施工良好性，其中包括養護溫度及時間、鑽孔深度、清孔及膠體混合良好性等因素，除此之外如施工廠商未選擇適當化學植筋膠，也會造成失敗工程案例，如幾年前日本北海道隧道上部板塊因錨栓錨錠失效引起之工安事件，更證明良好之結構物錨栓乃為工程安全性重要組件。 然為確保化學錨栓具備適當工程性能，國際大廠之化學植筋膠，均具備完整歐洲或美洲性能評定報告，我國目前雖有化學植筋膠產品，但我國仍未有適當評定制度，且市面上我國植筋膠產品也均未具備適當評定技術資料，因此本研究採用國外大廠生產之環氧樹脂化學植筋膠搭配結構補強最常用之#5(420Mpa)之鋼筋，植入C20/25(20.6Mpa)低強度及C35/43(34.3Mpa)高強度混凝土，採用歐盟EOTA EAD 330087與美國ACI 355.4化學錨栓評定準則，試驗與分析此國外化學錨栓單位面積黏結強度之性能。 本試驗參照了ACI 355.4-19評定準則，試驗化學錨栓在未開裂束制式抗張試驗中，其植於C20/25混凝土不同植入深度的單位面積黏結強度分別為16.309 N/mm²（4倍直徑）和15.558 N/mm²（7倍直徑），而植於C35/43混凝土植入4倍直徑深度單位面積黏結強度為17.304 N/mm²，皆符合ACI 355.4所規定之需求黏結強度；在裂紋束制式抗張試驗中，化學錨栓植入C20/25混凝土的單位面積黏結強度為10.518 N/mm²，植入C35/43混凝土單位面積黏結強度為11.922 N/mm²。由上述兩組數據顯示，錨栓單位面積黏結強度隨混凝土強度線性增加，因裂紋呈現於混凝土大致會降低錨栓黏結強度約35%~40%.。 由三組植筋施工影響性試驗結果顯示，一半清孔程序、混凝土潤濕、及鑽孔注水等錨栓施工等因子，對錨栓黏結強度影響性分別為12%、42%、及52%，混凝土含水性對黏結強影響性較顯著。 針對化學錨栓植入C20/25混凝土進行了埋入深度為111.3mm的抗張試驗結果顯示，化學錨栓在水平方向和垂直方向的植入無裂紋之C20/25混凝土之抗張試驗中，植筋單位面積黏結強度分別為14.238 N/mm²和10.435 N/mm²，其強度分別較垂直植筋條件下降低8%及33%，表明此化學錨栓於水平方向和垂直方向的植入C20/25混凝土條件下也能符合美洲規範之要求。由潛變試驗延時位移半對數圖顯示為第二階段潛變收斂行為，此植筋膠應可承受規範許可長期拉應力。由非束制式抗張試驗顯示，此植筋膠於未開裂混凝土具備承受適當拉應力，然於開裂混凝土時未具備承受適當拉應力之能力。 由分析結果顯示，於分析錨栓特性強度如採用EOTA混凝土強度分析因子，所得錨栓特性強度較符合實際觀察趨勢，由此可知歐盟分析公式上較符合。
並列摘要
Currently, chemical anchor has been widely utilized in concrete structural reinforcement, connection, or remediation of structural design deficiencies. However, effective application of chemical anchors in various engineering projects still heavily relies on the good construction performance, including curing temperature and time, drilling depth, drill hole cleaning, and adhesive mixture condition. It is about 15 years ago, a Hokkaido Japan tunnel slab fall down case is due to the selection of inappropriate chemical anchor fastener, therefore, the safety of engineering structures are closely related to the selection of proper anchor system. Generally, the widely used chemical anchor gels would receive European or American quality certification to ensure the appropriate engineering performance. While Taiwan do not have any appropriate anchor evaluation system and the common used chemical anchor gels in Taiwan are also lack of adequate technical data. Therefore, the objective of study is to use an international well known epoxy anchor gel conducting the local anchor assessment study. The assessment of chemical anchor tensile tests used the #5 (420Mpa) reinforcing bars and a C20/25 (20.6 MPa) low compression strength concrete and a C35/43 (34.3Mpa) high-strength concrete. The assessment study adopted the European Technical Approval Guideline EOTA EAD 330087 and the American Concrete Institute ACI 355.4 post installed chemical anchor evaluation criteria in the analyses. The unit area bonding strength of the chemical gel was obtained based the test from each test condition. Based upon the quality assessment analyses according ACI 355.4-19 standard, the unit area bonding strength for anchor installed in C20/25 concrete with 4d and 7d embedment were 16.309 N/mm² (4d) and 15.558 N/mm² (7d), respectively. While, the bonding strength was 17.304 N/mm² (4d) as the chemical anchor installed in C35/43 concrete with 4d embedment. As for test conducted in the cracked concrete, the unite area bonding strength for C20/25 concrete was 10.518 N/mm², and for C35/43 concrete was 11.922 N/mm², respectively. The comparison of the unit area bonding strength for these two sets test condition indicated that those values obtained from the cracked concrete test was 35%~40% lower than that of obtained from non-cracked concrete test, which indicated that the presence of crack near bonding anchor would significantly reduce it bonding strength. The results obtained from the hole cleaning sensitivity tests under dry substrate, installation in water-saturated concrete, and installation in a water-filled hole conditions indicated that, the unit area bonding strength for the test anchors were reduced about 12%, 42%, and 52%, respectively, in comparison with the value obtained from standard installation procedure. The study conducted for chemical anchor tests installed in C20/25 concrete with an embedding depth of 111.3mm, the unit area bonding strength was 14.238 N/mm² and 10.435 N/mm² respectively as the anchor installed in the horizontal and vertical directions. Both tests results are satisfied the ACI requirements and it is 8% and 33% less than that installed under vertical installed condition. The results obtained from creep tests also indicated the chemical anchor showed the second type creep behavior and will function well under long-term tensile force as specified by the standard. In addition, due to the concrete compression strength correction factor within the analysis for the characteristic tensile strength of anchor, the value obtained from the calculated according to EOTA procedure shown better value based upon engineering judgement. These research findings provide valuable engineering information for the applications of bond anchors.
參考文獻
1. ACI 318-19, 2019, Building Code Requirements for Structural Concrete and Commentary, American Concrete Institute, ACI Committee 318, Detroit, Michigan.
2. ACI 355.2-19, 2019, Qualification of Post-Installed Mechanical Anchors in Concrete and Commentary, American Concrete Institute, ACI Committee 355, Detroit, Michigan.
3. ACI 355.4-19, 2019, Qualification of Post-Installed Adhesive Anchors in Concrete and Commentary, American Concrete Institute, ACI Committee 355, Detroit, Michigan.
4. ASTM E488, 2018, Standard Test Methods for Strength of Anchors in Concrete Elements, American Standard of Tests and Material.
5. EN 1992-4, 2017, Eurocode 2: Design of concrete structures － Part 4: Design of fastenings for use in concrete, European Organization for Technical Assessment.