在建筑工程中，钢管是不可或缺的材料之一。其中，以“45厚壁钢管”为代表的高强度、耐腐蚀性和良好韧性等特点，使其成为承重结构、管道系统以及其他应用领域内不可替代的选择。本文将探讨45厚壁钢管在建筑结构中的应用与选择，并通过真实案例加以说明。

首先，我们需要了解什么是“45厚壁钢管”。这是一种按照中国国家标准GB/T 8162-2018制造的圆形无缝钢 tube，它们具有直径为φ42.3mm至φ219.1mm，壁厚为4.5mm以上的一般要求。在设计时，应考虑到施工条件、使用环境和预算等因素。

例如，在上海市浦东新区建设的一座摩天大楼，其核心筒部分采用了大量45厚壁钢管作为构件。由于摩天大楼对抗震性能有严格要求，这些高强度的钢管确保了建筑物在地震发生时能够维持稳定结构。这项工程不仅体现了“45厚壁steel pipe”的重要性，也展现了现代城市建设对高质量材料需求的大力追求。

除了承重结构之外，“45 thick wall steel pipe”也广泛用于水处理系统。比如，一家位于北京郊区的大型饮用水厂，对于保证输送清洁饮用水至千万人口区域，对于所有设备尤其是配套设施都提出了极高要求。在这里，利用40米长且口径达500毫米的46.9mm厚壁无缝圆形合金低碳镁合金铸造铁轨作为输送干燥后的饮用水到储罐所需的是一种特殊设计的人字型支架，这个支架由数十段48厘米长度、高10厘米宽度（即上述提到的“45 thick wall steel pipe”）组成，每一段均经过精密加工并焊接起来，以确保液体流动过程中的平滑传输，同时又能满足最高安全标准。

最后，“high-strength steel tube with a thickness of 4.5 mm”, 也被广泛用于基础设施项目，如桥梁修建和隧道工程中。例如，在杭州西湖附近进行了一项复杂的地铁隧道施工，该项目涉及多个相互连接但在地质条件下困难的情况下的隧道穿越，其中包括通过地下河流下沉地区以及穿过已有交通线路的小溪河谷。而为了抵御这些潜在威胁并保持最佳通行速度，这些关键地点必须使用最坚固可靠的材料来支持土壤压力，即这种类型最适合耐久性的"thick-wall high-strength steel tubes".

综上所述，“high strength, corrosion-resistant and good ductility” are the key features that make “pipe with a thickness of 4.5 mm” an ideal choice for various applications in construction projects, including structural support, water supply systems and infrastructure development.

By examining real-world examples such as skyscraper construction in Shanghai's Pudong New District, water treatment facilities in Beijing’s suburbs, and underground tunnel work beneath West Lake in Hangzhou, we can see how the use of these specialized materials ensures safety standards are met while also addressing unique engineering challenges.

In conclusion, "the application and selection of 'steel pipes with a thickness of 4.5 mm' in building structures" is crucial to ensure stability under extreme conditions like earthquakes or floods while meeting budget constraints and environmental considerations.

This versatile material is an indispensable component within modern urban landscapes where resilience plays a vital role towards securing future developments amidst challenging natural forces – be it against seismic waves or torrential waters from heavy rainfall events – ensuring reliable transportations networks stay operational at all times through the careful design process involving many experts who must balance budgets while prioritizing safety measures before making final decisions on their chosen solution set forth by engineers who have been working tirelessly behind scenes to bring this vision into reality; thus proving why no other material has proven itself more capable than "steel tubes having walls measuring precisely four point five millimeters".