The concern about historical heritage and its conservation has been growing in our society over time, having more and more constructions tagged as architectural heritage. This fact, together with the increase in new infrastructure and population density, makes crucial the determination of potential vibration affections in sensitive constructions generated by new buildings and mechanical surface excavations or blasting operations [1
], while the opening of underground excavations can also have an important impact [4
]. Some research has been done to define the impact of using construction equipment on sensitive constructions [6
] and identify the structural damage caused by vibrations [8
], as well as the prediction of the maximum vibration that can be generated [9
]. Amick et al. [10
] described an interesting investigation regarding the propagation of major vibration sources, such as the movement of heavy vehicles or construction activities, from the ground to more sensitive areas.
1.2. Literature Review
Vibration issues can be generated by the operation of construction equipment, blasting and traffic traveling. The potential damage to constructions includes superficial and structural damage [15
], caused by excavation and demolition activities or earth movement. Besides, it can also affect sensitive equipment, i.e., microelectronic manufacturing equipment, which is very sensitive to ground vibrations and individuals close to the vibration source [16
]. Usually, the vibration amplitude of traffic is not high enough to cause damage to a construction due to suspension systems and pneumatic tires [19
]. On the other hand, railways and trains can also have a significant impact on vibrations, making it necessary to apply countermeasures [20
The concepts of particle displacement, velocity and acceleration are used to describe ground vibration, being the peak particle velocity the most appropriate variable to assess the potential damage to a construction [14
]. Vibration amplitude is described by three components: two horizontal components, transverse and longitudinal, and one vertical component, which generally has the highest amplitude and it is easy to measure [21
The duration and amplitude of the vibration change depends on the type of operation and equipment, ranging from a high amplitude and short duration to lower and longer characteristics, respectively. The equipment or activities can be classified as continuous, excavation and vibratory compaction equipment, among others, and single impact with or without a high-rate repeated impact vibration, like a jackhammer or other similar breakers.
The maximum velocity component for construction vibration, peak particle velocity (PPV), is used as a descriptor of the wave effect. This preference results from the close association of construction vibration with blast vibration monitoring, where particle velocity correlates with the appearance of cracking [2
The vibration source creates a disturbance that propagates away, being the R-wave the primary concern for foundations close to the surface [2
]. According to Richard [22
], R-waves account for 67% of the total energy, S- waves for 26% and P-waves for 7% when the exciting force is applied vertically to the propagation direction. The vibratory excitation propagates radially outward, causing a spreading loss as the wave finds an increasing volume, reducing the amplitude of the displacement. The general expression to model the spreading loss is defined in Section 2.3
. When the rock mass is highly fractured and deteriorated, or it is a soil, its behavior is not perfectly elastic, having a damping effect, influenced by multiple variables such as the type of material, moisture or frequency of the vibration source. This behavior was defined by Telford et al. [23
], also explained in Section 2.3
, having two parameters, γ and α, that represent the geometric attenuation coefficient, depending on the wave type, and the attenuation coefficient of the material. Dowding [2
] and Jones and Stokes Associates [24
] gathered the typical values of the attenuation coefficient, however, there is a large possible range in each type of material. On the other hand, Sambuelli [25
] proposed an interesting approach to forecast the maximum particle velocity on the basis of blasting design and rock parameters, detailing an analytical approach to support the empirical expressions used. The dependence on frequency caused by construction equipment is commonly considered as weak. It is often assumed independent from frequency [26
]. Therefore, the greatest concern is related to the distance from the vibration source.
] and Hendriks [21
] gathered many of the damping coefficients depending on the type of material. Besides, [27
] mentions that it is a proper methodology to determine the impact to structures and people. However, most of the information is for soils and not for rocks. Besides, it analyses individual vibration effects, not the global effect of several equipment working at the same time. In this regard, Santamaria et al. [28
] suggested different γ coefficients for rock depending on the type of wave, body or surface, and for poor rock mass that still needs blasting operations.
The effect of vibration to constructions has attracted the attention of many researchers over time, focused primarily on the potential damage from mining and blasting [29
]. Kadiri et al. [30
] gathered an interesting revision of the empirical equations developed in recent decades to improve the vibration prediction caused by blasting.
Currently, there are many different standards used depending on the type of construction, structural conditions and age [24
], including specific criteria for sensitive and historic buildings [2
]. There is also an extensive knowledge of vibrations generated in linear constructions such as roads or railways. Crabb and Hiller [33
] measured vibrations from several types of construction equipment in a controlled experiment, while Jackson et al. [26
] and Hanson et al. [34
], provided a national approach to assessing vibrations from construction equipment in the USA.
Some literature is focused on defining the peak particle velocity (PPV) depending on the type of equipment [35
]. For instance, Hiller and Crabb [37
] and Jackson et al. [38
] developed an expression to determine the vibration generated by a roller drum at a short distance, taking into account the length of the roller drum. Moreover, Hanson et al. [34
] proposed an empirical equation to predict vibration from pile driving. Dowding [2
] also proposed an expression for the impact hammer based on experimental data. However, several machines work at the same time usually, which is necessary to analyze the overall vibration impact.
All this knowledge has fostered the development of international standards to provide guidance for building damage from mechanized construction, as well as blasting. The most common are the following: German Standard DIN 4150-3:1999, British Standard BS 7385-2:1993 and Swiss Standard VSS-SN640-312a:1992, all taking into account the effect on sensitive or historical constructions in all of them, but with different approaches. Additional research has been done regarding the maximum allowable vibration velocity, such as the American Association of State Highway and Transportation Officials [39
], that defines different allowable velocities for transient sources and continuous or frequent intermittent sources. On the other hand, Schiappa de Azevedo and Patricio [40
] considered that the maximum velocity permitted depends on the type of ground where the historical building is placed.
Several methods to reduce the vibration are proposed. One of the most common among them is a wave barrier, which cut the wave transmission from the source to the receiver. Wave barriers must be very deep and long to be effective, and they are not cost-effective for temporary applications such as pile driving vibration mitigation [15
]. Other measures or elements, like crushing equipment when working in concrete or hard rock can be used to reduce the vibration from a hydraulic breaker, however, it cannot always be applied [15
]. Other more general measures such as maintenance of the machines, reducing the time that different equipment are working simultaneously or their size can also be evaluated, but it is impossible to avoid the whole problem, and it is often not feasible [14