Detailed Survey of St. Martin’s Church, Bullring, Birmingham
Overview of Project
Castle Surveys Ltd was commissioned to undertake a comprehensive measured building survey, topographic land survey, and drainage survey of the historic St. Martin’s Church in the famous Bullring area of Birmingham. Given the importance of the church as one of the key landmarks within the city, the nature of the commission demanded a highly detailed approach: accurately documenting the complex architecture and mapping subsurface infrastructure. It utilized a combination of Leica RTC360 laser scanners, Leica TS16 total stations, drone technology, and comprehensive utility surveying to provide Castle Surveys with very accurate and detailed data that would serve as the basis for the future preservation and renovation processes to come on the church. In fact, this dataset would form the basis for digital twins, floor plans, elevations, and 3D models for accurate restoration and urban planning.
St. Martin’s Church: Its Historical Significance
St. Martin’s rightly is believed to be a landmark of great historical and cultural importance in Birmingham, as its roots go back to the 13th century. In 1873, it was rebuilt by J.A. Chatwin, one of the most noted Victorians, hence being a hallmark of the Victorian Gothic Revival style. Yet, parts of its original structure from the 14th century were preserved-the tower and spire-which justifies its historical value. In addition, it is still more famous for wonderfully decorated stained glass designed by the great artist Edward Burne-Jones and gives an assurance of its status as an architectural and cultural heritage site. In the hustle and bustle of the Bullring shopping area, St. Martin’s provides spiritual respite from that commercialism; its conservation is essential to retaining the historical identity of the city. The survey work carried out by Castle Surveys was thus very significant to ensure that this iconic building could be carefully preserved for future generations.
Castle Surveys was engaged to provide a comprehensive measured building survey, topographic land survey, and utility survey in order to meet the following objectives:
Obtain an as-built accurate record of the architectural details in the church both internally and externally for future conservation works.
Create a digital twin of the church by capturing accurate dimensions and feature sets in a 3D model for use in restoration planning and urban development.
Conduct topographic land surveys that map the surrounding environment to ensure an accurate understanding of the site with regard to the Bullring area. Conduct a drainage system survey and mapping, which involved in excess of 50 manhole lifts, providing detailed information on the design of the new drainage system, such as pipe sizes, invert levels, and construction types.
Deploy Leica RTC360 Laser Scanners for Precision
The use of Castle Surveys’ Leica RTC360 laser scanners was critical in attaining high precisions of the as-built environment of St. Martin’s Church with good efficiency. Indeed, the RTC360-known for its rapid data capture and millimeter accuracy-is of essence in surveying both the complex interior architecture and towering outside features of this church. Some identifying features about the Leica RTC360 laser scanner that made it ideal for the job were:
Data capture of 2 million points per second allowed the rapid collection of highly detailed point cloud data across the entire structure. High Dynamic Range (HDR) imaging to ensure colorized point clouds provided clear, accurate, visual representations of the church’s intricate features. A range of up to 130 meters, perfect for surveying the height of the spire, the roof, and other elevated sections of the church.
In addition, it had real-time registration that automatically aligned the scans while collecting, saving considerably on post-processing time.
These laser scanners have enabled Castle Surveys to create a digital twin of the church rapidly. It provided accurate 3-D models for architectural analysis, floor plans, and elevations.
Day Challenges Narrow Staircases, Underground Crypts and a Working Church
These were various challenges attendant to the historic and architectural nature of St. Martin’s Church. In most areas of access, the church presents a need for negotiating narrow spiral staircases and underground crypts with highly specialized equipment. The church was still active, so we had to negotiate services and events that could restrict access in specific areas.
Castle Surveys overcame these obstacles by deploying:
Experienced surveyors with expertise in navigating confined spaces and complex historical buildings.
RTC360 Leica scanners enabled fast data capture even in narrow and difficult-to-reach areas, such as spiral staircases and crypts. Closely collaborating with the head of the church, ensuring that this survey should be made without disturbing the activities of the church, our team planned scanning activities during off-peak hours, enabling us to perform the survey with no disturbance in the everyday life of the church
Leica TS16 Total Station for Survey Control and Topographic Land Surveys
Supplementing the laser scanning, Castle Surveys deployed a Leica TS16 total station to provide precise survey control and enable topographic land surveys of the area surrounding St. Martin’s Church. The high-precision and automatic target recognition of the TS16 were some of the reasons it was selected to map the site and its challenging-to-access urban environment.
Mapping terrain around the church: pathways, elevations, and urban features.
Tying data collected from laser scanning to an accurate, coordinated survey grid.
The highly detailed terrain models produced of the surrounding Bullring area provided essential data for future urban planning and development. Drone Technology:
The Roof, Tower, and Spires
The height of St. Martin’s Church, along with difficult access, meant that capturing the level of detail required in the roof, tower, and spires was only feasible through drone technology. Castle Surveys deployed drones equipped with high-resolution cameras to produce a point cloud of the church’s high elements to complement data from a ground-based scan.
This drone survey provided:
High-resolution imagery and detailed 3D data with regard to the roof structure, including condition and architectural features. Highly accurate measurement of the tower and spires to ensure every part of the church was accounted for in the digital twin. The use of drones allowed us to efficiently record and measure areas that could otherwise have presented a difficult access situation
Accordingly, Castle Surveys was commissioned to undertake a full utility survey of the drainage system surrounding the church, including over 50 manhole lifts to map the drainage infrastructure, thus providing engineers with the relevant data needed in designing a new drainage system.
Major elements of the drainage survey included:
Mapping the pipe network system-detailed records on size, direction, and construction type for each drainage pipe.
Gathering of invert levels, significant to develop the water flow within the drainage system and to design functional systems. Manhole surveying involved the documentation of construction materials, internal conditions, and dimensions. Provision of full data for providing in the design of an updated and more functional drainage system suitable for the site. Utility mapping was important for understanding current drainage conditions and informing future civil engineering designs.
Deliverables: Floor Plans, 3D Models, and Condition Reports
Among the various high-quality deliverables provided by Castle Surveys upon completion of this project for ongoing preservation and renovation at St. Martin’s Church was the following:
A 3D Revit model and Digital Twin of the whole church for detailed analysis of its architectural features.
2D floor plans, elevations, and sections of interior and exterior at building level.
A complete topographical land survey of the surrounding ground with detailed ground models and terrain data.
A comprehensive drainage report with pipe sizes, invert levels, manhole details, and construction types.
Conclusion
Castle Surveys Ltd’s detailed survey of St. Martin’s Church combined the latest technology with vast experience and detailed coordination with church officials to provide extremely valuable and accurate data. Twin technology digitally captured the most intricate architectural features of the church for the project, as well as provided key topographic land surveys and utility surveys important for future restoration and civil engineering work. Applying Leica RTC360 laser scanners, Leica TS16 total stations, and drone technology guaranteed that Castle Surveys preserved the rich history and architectural beauty of St. Martin’s Church for future generations to come.
