The following are examples of past research undertaken by Dr Martinez-Vazquez:
Earthquake, wind, and fire: joint effects on structures
Design frameworks worldwide consider natural or man-induced hazards to be statistically uncorrelated. This view has dominated engineering practice for decades; however, evidence suggests that such events could, in fact, coincide, thereby increasing the demand for infrastructure resilience. The continuous flow of wind raises the question of whether the forces it generates should be accounted for during earthquake-resistant design. Historically, forces of different natures have been seen to interact, causing damage that current design frameworks cannot prevent. Therefore, we must reflect on current engineering practices and make the necessary changes to minimise risk.
Analysis approach
This investigation addresses this knowledge gap by exploring the potential effects of earthquakes, wind, and fire acting on buildings. It estimates strength reduction factors that could potentially integrate more robust performance-based design initiatives. This study considers a range of historical earthquake records, wind speeds, and temperature gradients affecting steel and concrete structures to provide insight into the degree of deterioration that combined hazards could impose on infrastructure, which could eventually translate into a change in their initial ductility or, in extreme situations, total collapse.
Source: Martinez-Vazquez P, 2024. Earthquake, wind, and fire: joint effects on structures. Cogent Engineering, 11(1), 2423849.
Design Spectra for Wind Loading
Design spectra are normally applied in Seismic Engineering where it is assumed that the inertial forces induced by the horizontal accelerations acting at base of the structure are fully correlated. In the case of wind loading the amount of energy imparted by the wind to the structural system can be estimated for point-like structures as well as for large areas by considering suitable spatial correlation laws. In addition, the use of generalised techniques allows considering the dynamic response of single oscillators whose ensemble response constitutes a design spectrum which in turn can be used to carry out modal analyses.
Comparison design spectra versus experimental results
The spectral technique has already been developed for synoptic and non-synoptic winds acting on buildings with specific geometry, yet there is a need to generalise the method to produce wind design spectra for any building and wind regime.
Source: Martinez-Vazquez P, 2016. Wind induced vibrations of structures by using design spectra. International Journal of Advances Structural Engineering, 8(4): 379-389.
Wind turbine tower collapse cases: a historical overview
Wind turbines are conceived, designed and operated to interact with the environment, including through extreme events. However, engineering malpractices combined with human or mechanical errors and defects of constituent members and materials, still result in hundreds of structural collapse cases annually. It seems, therefore, necessary to reflect on factual wind turbine performance against the target performance. This investigation summarises the most severe tubular wind tower collapse incidents recorded over the past four decades, provides an account of the damage and discusses the respective potential causes.
Failure type distribution of wind turbine incidents recorded between 1980 and 2016 (CWIF, 2017)
The results obtained indicate that, although accidental load induced by typhoons and storms is the most usual reason of failure, fatal events concentrate at either early or late stage of the designed service life. Unexpected load conditions seemed to derive from defective blade positioning or braking, which in turn over-stress areas of transition such as joints and openings. However, a critical examination of design standards suggests that, in general, wind turbine towers as designed and built nowadays are stable and reliable. Hence, the chain relationship determined by the design, manufacturing, construction, operation and maintenance, needs enhancement and further cohesion, at the time that our understanding of and adaptation to extreme events continues to develop.
Source: Ma Y, Martinez-Vazquez P, Baniotopoulos C, 2018. Wind turbine tower collapse cases: a historical overview. Structures and Buildings, 172(8): 547-555.
Life cycle assessment of an urban vertical farm benchmark from construction to dismantling and recycling
Urban Vertical Farming helps mitigate problems associated with limited crop growth due to unstable land and climate conditions. It is expected that, under suitable control, such as soilless technology, environmental control systems, automated management, and other core working principles, food crops can be grown continuously without being affected by seasonal variations. However, the amount of energy required to create optimum cultivation conditions can lead to high operating costs (especially in Europe) and other environmental impacts. In this study, we discuss those issues in relation to the construction, operation and management of an urban vertical farm, via life cycle analyses. The study considers scenarios that combine the supply of building materials, building design life and transportation distance of the products, while exploring ways to reduce carbon emissions through wind energy harvesting.
(a) Contribution of building systems and mechanical transport to environmental impacts during the construction phase and (b) Contribution of construction materials to environmental impacts at the construction phase
The results obtained indicate that the investigated urban vertical farm yields a GWP of 5.43 kg CO2 eq per kilogram of lettuce under the current grid structure, which is 9–14 times higher than that of traditional open field farming. However, the main reason for the exponential increase in GWP is the power consumption of artificial lighting and HVAC systems. Among these, 3.61 % of life-cycle carbon emissions can be saved by recycling waste lettuce at the use and production phase. The dismantling and recycling phase can recover 4.06 % of the life-cycle carbon emissions by recycling materials. Furthermore, the study results indicated that the clean energy produced by wind turbines can reduce carbon emissions by up to 2.39 %.
Source: Xie S, Martinez-Vazquez P, Baniotopoulos C, 2025. Life cycle assessment of an urban vertical farm benchmark from construction to dismantling and recycling. Building and Environment, 286, 113729.
Crop lodging induced by wind and rain
A methodology to estimate wind and rain effects on the four main growth crops in the United Kingdom is presented. The method is based on simulated weather scenarios acting on synthetic plants over a period of thirty years. The environmental data is generated with the UKCP09 Weather Generator considering future climate scenarios whereas plants are modelled as simple oscillators characterised by their mass, stiffness and damping. The joint probability of occurrence of wind and rain are estimated together with the conditions in which lodging would occur.
Representation of plant failure of a 20-plant database (left) and 10,000 plant sample (right)
The paper shows that the dynamic response of plants varies with season being the first three months of the year the most critical whilst the plants’ performances define crop failure velocities ranging between 4 ms−1 and 23 ms−1 and associated failure rates of 50% and 5% per unitary velocity.
Source: Martinez-Vazquez P, 2016. Crop lodging induced by wind and rain. Agricultural and forest meteorology, 228: 265-275.
Work recognition model for a higher education unit
Higher Education frameworks have a strong focus on increasing students’ satisfaction. This vision increases expectations on academic performance that often derive from stringent output measures for staff. The combination of internal and external demands for workers, such as those derived from their interaction with society, could create inadequate working conditions, which highlights the need to develop objective, rational, and robust mechanisms to distribute roles and responsibilities more fairly. This paper introduces a work recognition model for managing higher education units. It accounts for individual effort per discretised academic activity over a range of teaching, research, and administration duties.
Idealised yearly fluctuation of workload per area
The model integrates standard academic activities into a mathematical framework characterised by continuous derivable functions that can be used to visualise fluctuations of workload across a complete academic year. The established framework enables optimisation of workloads through redistribution, moving away from diagnosing issues experienced by individuals subject to imbalanced or unfair workloads, to propose a practical solution. It is also possible to enhance the architecture of the proposed model to incorporate further activity or allowances and potentially increase robustness. In addition, the numerical model is relatively easy to implement in a variety of platforms. The proposed model was tested on a case study including 26 academics, mixing three-legged and teaching-focused contracts, showing how it decreases the relative differences of workload by a proportion of 4:1, after redistribution.
Source: Martinez-Vazquez P, 2023. Work recognition model for a higher education unit. Cogent Education, 10: 2248912.