介绍
Introduction
1
在后张有黏结预应力混凝土结构或构件中，预应力筋的孔道宜由浇筑在混凝土中的刚性或半刚性管道构成，或采用钢管抽芯、胶管抽芯及金属伸缩套管抽芯等方法进行预留。波纹管按材质可分为金属波纹管和塑料波纹管；按截面形状可分为圆形和扁形；按径向刚度可分为标准型和增强型。其主要作用是保证孔道的稳定性，并确保能够在混凝土浇筑过程中保持原有的形状，传递黏结应力。
In post-tensioned bonded prestressed concrete structures or components, the ducts for the prestressing tendons are typically formed using rigid or semi-rigid pipes embedded in the concrete, or by methods such as steel pipe extraction, rubber pipe extraction, and metal expansion joint extraction. Corrugated pipes can be categorized based on material into metal and plastic types; by cross-sectional shape into round and flat shapes; and by radial stiffness into standard and reinforced types. Their primary role is to ensure the stability of the ducts and maintain their original shape under the weight of the poured concrete, thus facilitating the transfer of bonding stresses.
2
预应力筋通常由单根或成束的钢丝、钢绞线或钢筋组成。根据施工方法的不同，预应力筋可分为有粘结预应力筋和无粘结预应力筋。有粘结预应力筋是在混凝土构件或结构制作时预留孔道，然后进行混凝土浇筑，待混凝土达到设计强度后张拉并锚固，最后进行孔道灌浆与封锚。无粘结预应力筋则不直接接触混凝土，带有防腐隔离层和外护套，适用于特定的施工要求。
Prestressing tendons are usually composed of single or bundled steel wires, steel strands, or rebar. They can be categorized based on the construction method into bonded and unbonded prestressing tendons. Bonded prestressing involves leaving ducts in the concrete component or structure, pouring concrete, curing it, threading the prestressing tendons into the ducts, and then tensioning and anchoring them once the concrete reaches the required strength, followed by grout filling and anchoring. Unbonded prestressing tendons, however, do not come into direct contact with the concrete and are protected by a corrosion-resistant layer and an outer sheath.
2
锚垫板是预应力张拉施工中的一种预埋构件，主要用于传递和分散压力，减少混凝土中的引力集中，防止预应力张拉过程中混凝土开裂和破坏。其设计可以有效分散锚具的受力面积，提高结构的稳定性。
Bearing plates are embedded components used in prestressing tensioning operations. Their primary function is to transfer and distribute pressure, reducing the concentration of stresses in the concrete and preventing cracking and damage during prestressing. The design of bearing plates helps to effectively distribute the load area of the anchoring device, enhancing structural stability.
2
螺旋筋的主要作用是提高锚下局部混凝土的抗压强度。它能够有效防止在预应力筋张拉时因集中应力产生的开裂及混凝土压碎现象。通常在锚垫板后配置螺旋筋，以增强混凝土的抗压能力。
The role of spiral reinforcement is to enhance the compressive strength of the local concrete beneath the anchor and to prevent cracking or crushing of the concrete due to concentrated stresses during the tensioning of prestressing tendons. Spiral reinforcement is typically placed behind the bearing plates to improve compressive strength.
3
锚具分为两大类： (a) 张拉端锚具：安装在预应力筋端部，并在张拉过程中始终保持对预应力筋的锚固状态。常见的类型有用于张拉钢绞线的夹片式锚具（YJM）、用于高强钢丝的钢制锥形锚（GZM）、用于镦头后张拉钢丝的墩头锚（DM）、用于精轧螺纹钢筋的螺母（YGM）以及用于多股平行钢丝束的冷铸镦头锚（LZM）。 (b) 固定端锚具：安装在预应力筋端部，通常埋入混凝土中且不用以张拉，也被称作挤压锚或P锚。
Anchors can be divided into two main types: (a) Tension End Anchors: Installed at the end of prestressing tendons and designed to maintain anchorage during the tensioning process. Common types include clip-type anchors for tensioning steel strands (YJM), steel conical anchors for high-strength steel wires (GZM), head anchors for post-tensioning high-strength steel wires (DM), nut anchors for precision-rolled threaded bars (YGM), and cold-cast head anchors for multi-strand parallel wire bundles (LZM). (b) Fixed End Anchors: Installed at the end of prestressing tendons, typically embedded in concrete, and not used for tensioning. Also known as compression anchors or P-anchors.
3
限位板在预应力张拉过程中用于固定锚具夹片。适当的限位距离（限位板的槽深）可以使锚具回缩量达到最小。回缩量的测量方法很简单，即限位板的槽深减去锚具夹片张拉后的外露部分。
Limit plates play a role in fixing the anchor clips during prestressing tensioning. An appropriate limit distance (the depth of the limit plate slot) helps to minimize the retraction of the anchor. The simplest method to measure retraction is to subtract the exposed portion of the anchor clip after tensioning from the depth of the limit plate slot.
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