He also referred to the different types of studies that are carried out before erecting a building.
By Gissel Taveras
El Inmobiliario
SANTO DOMINGO- This hurricane season is projected to be doubly active by the National Oceanic and Atmospheric Administration (NOAA), expecting between 17 and 25 storms, of which between 8 and 13 may reach the category of hurricanes, some of which could hit Dominican territory.
In that regard, Osiris de León, a geologist who chairs the National Committee for Infrastructure Assessment in the face of climate change, recommended that the private sector, companies and citizens adopt plans and programs early on to reduce vulnerabilities in buildings, power lines and flood-prone areas.
“As well as in effective drainage systems that quickly drain rainwater into the sea or neighboring rivers, in stabilizing unstable slopes such as those of the Cazabito road on the way to Constanza, the Gurabo road to Puerto Plata, the El Seibo road to Miches,” he indicated.
He reported that caution should be exercised on the Baní to Ocoa road, the Ocoa to Piedra Blanca road, the Barahona to Paraíso road, the Tenares to Gaspar Hernández road, and the Sánchez to Las Terrenas road, all of which have suffered landslides in the past that have blocked access to the communities.
“Likewise, rivers that are silted up, such as the Nizao, the Nigua, the Yubazo, the Haina, the Baní, the Jura, the Panzo, the Birán, the San Juan, the Yaque del Norte and Yaque del Sur, the Nagua, the Yuna, the Camú, the Boba, the Ocoa, and many others, must be channeled in the critical sections to avoid scouring at the approaches and at the bases of the bridge support piers.”.
He pointed out that from Hurricane David to Hurricane Georges, more than 200 bridges have been destroyed or severely damaged by river floods that have not found an adequate cross-section for the river traffic of the peak flood.
Soilstudies
Regarding soil studies in buildings, de León stated that many are limited to soundings with standard penetration tests (SPT), which are insufficient.
“A sounding is representative of its vertical axis, but often, especially in heterogeneous soils, conditions change abruptly and we find ourselves with terrains of very poor geotechnical behavior and very poor seismic response, which is always undesirable,” he reported.
He noted that modern soil studies are carried out by combining geological and geophysical studies using seismic tests for shear waves (Vs) and geoelectric tests to locate caverns and soft clay pockets.
He added that hydrogeological studies are used to define the water table level and its seasonal variations based on weather conditions, the direction of groundwater flow, and the pressures exerted on neighboring structures.
Other studies are also used such as: Mechanical soundings for bar penetration resistance tests (SPT) and sampling for visual classification and for physical laboratory tests such as granulometry, density, Atterberg limits in clays, compressive strength (q) and shear stress (C), stiffness and deformation modulus, angle of internal friction, geotechnical.
“Good studies must be done to define the subsurface stratigraphy, the soil's load-bearing capacity and the foundation horizon, the most suitable type of foundation or foundation depth to reduce differential and total settlements that can crack and damage the structure, and to obtain the best seismic response,” he explained.
This, the expert explained, is because in soft soils seismic waves are amplified, seismic accelerations increase, shear forces increase, and many structures collapse during large earthquakes.
