troubl- Using laser scanning to capture the new Höllentalklamm (Hell’s Gorge) bridge in the German Alps

Author: Thomas Schock

The Höllentalklamm - in English “Hell's Gorge” - near Garmisch-Partenkirchen is a unique natural spectacle 1,000m high in the German Alps. It’s part of the hiking route to the Zugspitze peak, a connection only made possible due to a historic bridge across the gorge, built in 1905. Due to its age and deterioration, the bridge and several footbridges had to be replaced in 2020. The local members of the德国高山协会（DAV）raised money for the 250,000-euro project and found two crucial corporate sponsors – the transport infrastructure specialistsZüblin / StrabagandThyssen-Krupp。

A Leica Geosystems partner, STRABAG used a laser scanning solution to capture the new bridge digitally. The survey was a demonstration of the scanners ability to perform even in this ‘hellish’ environment. The digital plans created will be used for future maintenance.

取代历史悠久的桥梁

从1902年到1905年，峡谷上第一座桥梁的建设花费了600个工作日。工程的一项令人印象深刻的壮举，几乎是手工完成的，没有电或现代机械。如今，建筑材料至少可以用直升机以1045m的速度运送到霍利纳特入口。从那里开始，由苏布林 /斯特拉巴格工程师，当地建筑公司FlorianDörfler和Dav志愿者组成，需要将组件拖到200m范围的建筑工地。为了将重量超过四吨的桥运送到狭窄的峡谷中，它分为大约600个单独的零件。定制的桥梁和人行道元素是由祖布林在勃兰登堡Hosena的结构性钢铁制品细分进行了预制的。

尽管几乎是完美的初步计划，但一些障碍是不可避免的。事实证明，卸下桥支架的岩石被锚定的岩石要比预期的要困难得多。尽管如此，构建只花了四个星期。Züblin网站经理PhilippSchön总结说：“在HöllentalkLamm非常特别的背景下，准备工作，最后是该赞助项目的执行真是太棒了。来自各个项目参与者的团队就像一台油腻的机器一样，共同努力。”

便携式，健壮且高度准确的激光扫描解决方案

Once the bridge was replaced, Philipp Mielke, Technical Group Manager at STRABAG with Johannes Zettel, Marketing and Thomas Schock from Leica Geosystems used both theLeica RTC360andblk2go使用激光扫描捕获新拱桥的数字双胞胎。

RTC360在高度便携的同时提供了干净且高度准确的点云。实际上，它与碳三脚架一起安装在背包中，并从停车场远足到峡谷。它也很健壮-IP54的额定值，因此能够应对水的溅水 - 非常适合湿山环境。

The BLK2GO is a handheld imaging laser scanner that recreates spaces in 3D as you move. The operator - Schock - was able to carry it in one hand and scan while walking, making it easy to stay balanced and aware of hazards on the slippery terrain. The software used to process the data wasLeica Cyclone寄存器360，，，，Leica Cloudworx，，，，Leica Truview EnterpriseandLeica Cyclone 3dr。

从捕获桥梁到数据共享

使用RTC360，Schock在五个角度上进行了扫描：在桥上进行了三场扫描，两侧两侧从50m远，朝它看。这创造了各个侧面狭窄峡谷的桥和岩石的图片。在五次曝光停止时使用扫描仪拍摄HDR图像，以允许对黑暗区域（隧道）和明亮区域（阳光全高的阳光下）进行RGB检查。在谈到异常条件时，肖克说：“在霍伦特尔克兰姆（Höllentalklamm）中需要确定的脚和高度的头！但是，轻巧的RTC360迅速掌握了上升。”

Schock使用BLK2GO手持式成像激光扫描仪完成了大约10分钟的步行路程，覆盖了桥的每一侧的150-200m地形。这是在连接区域的足够重叠来完成的，以允许将连续的轨迹与旋风寄存器360的Cloud2Cloud算法联系起来。

Following scanning, Cyclone REGISTER 360 was used to import, prepare and optimise the data to deliver a LGS data set to use in other Leica Geosystems and third-party applications. TruView Enterprise was used for visualisation, a quick and easy way to share point cloud data with others involved in the project, and Leica Cyclone 3DR will be used to mesh the data for the gorge and tunnels.

即使在“狭窄和约束条件”中，令人印象深刻的结果

The Höllentalklamm bridge project was an ideal opportunity to put the latestLeica Geosystems 3D激光扫描设备to the test. Although the location was hard-to-access and the weather conditions were challenging, the laser scanners were as easy-to-use there as they would be at sea level.

肖克说：“两种扫描仪都按预期进行，结果超出了预期。”Strabag的Philipp Mielke同意：“使用RTC360的桥梁扫描结果非常好。即使在这些狭窄且受约束的条件下，我们也没有问题扫描桥梁。”该公司已经在其他隧道和建筑项目中使用了RTC360，目前正在进行或计划进行BLK2GO的进一步测试。