Wireless Crack Gauge Monitoring: Providing Reliable Data with Advanced Technology

Crack gauge monitoring is an essential part of any construction monitoring plan. In New York City, crack gauge monitoring is required as part of TPPN #10/88 in the building code, and for the preservation of historic landmark buildings and structures.

A crack gauge monitoring program generally consists of both a physical inspection and photographic survey in the pre-construction phase, as well as crack gauge measuring equipment that is in place throughout the construction process. Crack gauge monitors and sensors are positioned to monitor existing cracks in adjacent structures, and these cracks are continuously monitored for changes or displacements.

Wireless crack gauge monitors are the best option for many types of construction projects and sites. The use of technologically-advanced wireless sensors and monitoring equipment provides a number of benefits to projects that require crack gauge monitoring. These benefits are found in all phases of the crack gauge monitoring process, including measuring, collecting and transmitting data to the client. They include:

Versatility – wireless crack gauge systems can be used in any number of structure types, including tunnels, buildings, and bridges. Systems can be used in a variety of construction projects. Wireless crack gauge monitors are also a better option than tell-tale crack monitors for sites that have either limited access or for hard-to -reach areas.

Reliability and accuracy – Wireless monitoring systems have the ability to measure data on a constant basis; all data is recorded in real time and transmitted to the client with no waiting time via cell phones directly to the client’s computer. Any issues such as displacement can be reported in real-time to minimize risk. Reports can be created on a custom basis, depending on the needs of each client and project. Monitors have a five-year battery life, so there is virtually no interruption in service.

When used as part of a complete solution, wireless crack gauge monitors are among the most advanced monitoring equipment that can be used in any construction monitoring program.

Protection of Landmark Buildings in New York City

New York City’s historic landmarks are an integral part of the city’s vibrant culture and landscape.   The City of New York established the Landmarks Preservation Commission in 1965, in response to the demolition of a number of historically relevant properties, particularly the original Pennsylvania Station that was built in 1911.  According to the LPC, a landmark is defined as “a building, property or object that has a special character or special historical or aesthetic interest or value as part of the development, heritage, or cultural characteristics of the city, state, or nation.”

Since then more than 36,000 properties in New York City have been designated as landmarks. Once a building has been designated as a landmark, the LPC is required to approve any alteration, reconstruction, demolition or new construction. This is required for individual landmark buildings as well as buildings within a designated historic district.

Although part of the landmark preservation regulations includes maintaining a building’s architectural style and character, there are more than aesthetics involved. Historic structures can be more susceptible to damage from construction activities than newer more modern buildings.  Vibration levels from construction activities in areas adjacent to historic buildings can also impact these buildings and their foundations. Historic buildings can be significantly affected by demolition and foundation work being conducted in the vicinity.

New York City building code requires surveying and monitoring of construction work within a 90-foot radius of any designated landmark. Technical policy TP 10/88 details the types of surveying and monitoring that must be in place at these building sites. A complete monitoring program in a landmark building or adjacent area includes a combination of services such as pre-construction surveys (existing conditions photographic documentation), Optical Structure Survey, remote or manned seismographic vibration monitoring equipment, crack gauge monitoring, and tilt meter monitoring.

Pre-construction surveys and ongoing vibration monitoring are crucial for detecting any potential issues prior to the start of a construction project or during the project. Monitoring and surveying are part of a comprehensive approach that can serve to protect  not only the historical structures and residents of the area, but other stakeholders involved, including developers, building owners, contractors and site engineers.

Detailed information and latest updates on the NYC LPC can be found at: https://www1.nyc.gov/site/lpc/index.page

Innovative Monitoring Technology Key in Bridge Preservation Programs and Solutions

A Bridge Preservation Guide published this spring by the Federal Highway Administration outlines the importance of bridge preservation programs and other solutions as part of an overall necessity to address the nationwide infrastructure challenges in the US.

According to 2017 bridge data collected and released by the FHWA, of the nation’s 612,677 bridges, more than 54,000 of these are rated “structurally deficient,” while more than one-third of all bridges in the U.S. have demonstrated repair needs. As a result, bridge repair and rehabilitation remain among the top priorities for transportation departments throughout the U.S.

The FHWA notes that limited funding for infrastructure makes it necessary for federal, state and local governments to implement cost-effective methods and programs that seek to extend the safe service life of bridges through a variety of preservation and rehabilitation programs.  These programs include a combination of solutions, including developing and implementing routine maintenance for various bridge components, both surface and structural. Bridge preservation programs also involve assessing and monitoring the structural health and integrity of existing structures, including mandatory inspections and methods of damage detection.

There are various ways that innovative monitoring systems, including continuous, wireless and remote systems, are being used in structural health monitoring (SHM) programs for bridges and other structures. The FHWA notes that technical innovations and advancements in monitoring equipment and data gathering can be incorporated into various phases involving bridge construction or repair. Some of these areas include early detection of structural defects and ongoing monitoring and data collection related to the study of traffic or environmental impact. Monitoring systems can also be implemented for design and pre-construction activities, as well as new bridge construction. These innovations can be included in both the design and construction phases of both bridges and sub-structures.

As the average age of bridges in the U.S. continues to climb, and as more bridges each year approach the end of their design or service life, it’s imperative for government and transportation officials at all levels to look to innovative, new technologies for early detection, assessment, monitoring, and collecting data, as part of an overall plan to restore the infrastructure.


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Facts about Construction Monitoring for MTA-related Projects

Construction monitoring requirements for projects taking place in or near NYCTA structures or tunnels are somewhat different than other construction projects. Pre-construction surveys and monitoring are required in most scenarios when these activities are taking place in or around NYCTA structures and other transit tunnels. Surface construction activities, including foundation work, NYCTA structures can adversely affect underground structures or the subway system. In addition, underground tunnel and subway construction projects can produce vibration levels that can potentially damage nearby streets, foundations, buildings and other structures.

In New York City, the Metropolitan Transportation Authority (MTA) requires vibration monitoring anytime drilling or excavating is done within 75 feet of a structure. Unlike other construction projects, the MTA requires that all monitoring in these projects be manned by a field technician. Remote monitoring is not permitted in these instances. All field technicians monitoring NYCTA structures and tunnel sites must be MTA Track Certified and OSHA 10 compliant.

MTA projects most often involve a combination of pre-construction inspections, optical surveying, vibration monitoring, and crack gauge monitoring. In the case of vibration monitoring, the MTA requires that a monitor be placed every 25 feet on structures adjacent to the construction activity. Construction site monitoring reports are provided on a weekly basis to the MTA while activity is ongoing, during various project phases. In the event of a trigger event, monitoring technicians will immediately notify both construction personnel and the MTA.

The Port Authority of New York and New Jersey has similar requirements for construction projects involving the Port Authority Trans-Hudson (PATH) transit system in Northern New Jersey.

Benefits of Construction Monitoring Services on a Project Site

There are several ways that a construction site project can benefit from construction monitoring services. Many urban projects in any of the five boroughs of New York City have set requirements for various construction monitoring services, such as optical surveying, existing conditions documentation, and vibration or crack gauge monitoring. While there are specific requirements for construction monitoring depending on the type of work being performed or related to the proximity of landmark buildings and historic districts, there are also a variety of ways construction sites will benefit from monitoring services.


Safety Precautions

Safety is always a paramount concern on any construction site or any project, no matter how large or small.  Construction monitoring services are part of a safety protocol that can better identify any safety risks at different stages of any building project. Pre-construction or existing condition documentation surveys can be the first step in assessing a building site or structure for any pre-existing damage, or conditions for which precautions need to be taken. Pre-construction surveys can also be used in identifying any potential hazards or defects that could cause harm to workers, nearby residents, or the general public.

Along with pre-construction surveys, additional ongoing monitoring services that continue during the project, such as vibration and crack gauge monitoring, can alert engineer and construction staff to any potential safety issues that can arise during the project, including structural changes or dangerous vibration levels.


Risk Management

Construction monitoring services are also a crucial part of a complete risk management plan pertaining to any construction site or project. Existing conditions surveys, optical surveying, and other monitoring services and the related data and reports are all essential for the protection of stakeholders in any building site. Detailed reporting and documentation of existing conditions are necessary to address any issues or areas that may need to be addressed prior to the beginning of the construction process.


Mitigate Potential Damage

Ongoing construction monitoring, whether remote or manned, can help prevent any potential damage that can result from any number of construction activities, from pile driving, excavation, drilling, blasting, tunneling, or even operating construction vehicles. For example, when on-site continuous vibration monitoring is used during a construction project, real-time data is reported. If maximum peak particle velocity levels are reached, project managers or engineers are alerted and necessary modifications can be made on site to prevent any structural damage.

A comprehensive site monitoring protocol can help protect not only the structure, but also profits and assets of the contractor, developer and property owner.

When Is Continuous Vibration Monitoring Performed?

Vibration monitoring is one part of a complete construction monitoring program often required for many construction projects, particularly in New York City or other urban areas. For example, New York City building codes require a monitoring program in many instances, such as when underpinning work is being completed, or within a 90’ radius of a NYC landmarked building/historic district(as per NYC Building Code TPPN 10/88).

Vibration monitoring is specifically used to monitor potentially damaging ground vibration that can occur with many common construction activities. Excavation, pile driving, blasting, demolition and movement of construction vehicles are among the typical construction activities that can cause ground vibration. High tech seismographic equipment, instruments, and systems are used to measure and record ground vibrations throughout a construction project for maximum accuracy and efficiency. Equipment is either monitored remotely or is manned by trained field technicians.

Since the needs of each construction project may vary depending on the specifics of the project, site, locations and a variety of other factors, each construction project benefits from a custom monitoring program. A monitoring program may involve a combination of services, including pre-construction survey, vibration monitoring, crack gauge monitoring, optical structural surveying, and tilt meter monitoring.

Vibration monitoring is often performed on a continuous basis for a variety of reasons. Prior to construction, continuous vibration monitoring is used to establish a baseline of ground vibrations prior to beginning any construction activities. During the construction activities, continuous remote monitoring can be used to measure peak particle velocity and provide real time constant reporting and results to the site engineer or other construction site managers. Continuous monitoring allows for reporting all readings, including any vibration spikes in real time.


When is Vibration Monitoring Necessary?

Many construction projects in New York City, Northern New Jersey and the surrounding metro-area will require vibration monitoring plans and programs before work can begin on a construction site.

Construction activities can create vibration levels that can potentially lead to structural damage within surrounding buildings. As a result, many of these activities create a need for vibration monitoring. In addition, in New York City, Technical Policy and Procedure Notice TPPN #10/88 requires preconstruction surveys, vibration monitoring, optical structural monitoring & crack gauge monitoring on all landmarked structures within 90 feet of the site lot (this also includes structures within a historic district).

Below is a link to discover New York Landmarks that identifies both historic landmark districts & individual land mark structures.


Construction Activities Requiring Vibration Monitoring Services

Vibration levels are a concern for a variety of construction activities conducted within urban landscapes. Among the more common scenarios and activities that may require vibration monitoring include demolition, excavation, blasting, pile driving, or even heavy equipment operation. Building codes in urban areas include structural and safety regulations that may require vibration monitoring and systems be put in place to ensure that vibration levels don’t exceed specified thresholds.


NYC Landmark Buildings and TPPN 10/88

In New York City, as per TPPN 10/88, all construction activities within a 90’ radius of a landmark building or district require pre-construction surveys, optical structure monitoring, crack gauge monitoring and vibration monitoring services.

TPPN 10/88 creates a baseline which legally protects contractors and property owners in various phases of a project, including pre-construction, during construction and post construction. To be compliant with TPPN 10/88, an ongoing construction monitoring program must be put into place prior to the beginning of the project.

Along with Vibration Monitoring, TPPN 10/88 requires pre-construction surveys, optical structure monitoring and crack gauge monitoring as part of the monitoring and precautionary procedures.


Vibration Monitoring Types

There are two types of vibration monitoring used during construction, depending on the types of structures surrounding the site. For example, MTA structures require manned vibration monitoring.

Remote, or wireless vibration monitoring: The vibration monitoring instruments are placed on or adjacent to the job site and monitor continuously with real time readings and alerts reported to the client as specified or required.

Manned monitoring: With manned monitoring, the equipment and instruments are installed and are carefully monitored by a trained field technician, who is in communication with site engineers, construction managers or other site personnel.

Key Factors in Choosing a Construction Monitoring Services Firm in NYC

Many construction projects in New York City require hiring a construction monitoring services company in order to comply with NYC local building codes. Developers, contractors, project managers, and homeowners are among clients often required to use specialized monitoring to be in compliance with TPPN 10/88 due to the proximity of the construction site to historic building and neighborhoods. Building owners and contractors alike need to take the proper steps necessary to protect their assets, infrastructure, buildings, as well as neighboring properties. When hiring a monitoring services firm, there are some key factors clients should keep in mind in order to remain compliant and protect their assets.

Comprehensive solutions: Consider selecting a firm that can provide a full range set of solutions for a project, including working with you to create a plan that will address the needs for the entire project,  from pre-construction surveys or existing conditions documentation through all monitoring deemed necessary for each stage of the construction project, including thorough reporting before, during and after their project.

State of the art monitoring equipment: The specialized areas of vibration monitoring, crack gauge monitoring and geological monitoring require highly precise equipment and devices. Look for service companies using the most accurate state-of-the-art  industry equipment available, for both on-site and remote monitoring needs. Firms should demonstrate up to date knowledge of technologies and systems, while employing expert field technicians. This includes capability of providing remote alerts of real-time readings of equipment.

Communication and collaboration: Constant communication and reporting with each client is crucial while conducting vibration and crack gauge monitoring and other surveying services. This communication and reporting is vital before, during and after the construction project, and will vary depending on the type of project and the site. Highly skilled technicians and experts, plus thorough and extensive reporting, are key for meeting compliance, structural and safety requirements of any project. This includes collaborating and consulting with site owners, developers, engineers and other experts on the project.

Accurate and precise monitoring, highly skilled technical expertise, plus thorough and timely reporting are all crucial to ensuring that compliance and safety requirements are met and that building assets and values are protected and preserved in any urban construction project.