dictamen meIn our May Update, we reported on our meeting with Mayor Davalos, our top priority being City action on the undermining of Los Pinos pavement.
In June, we interviewed Civil Engineer Antonio Mercurio, of Construcciones Mercurio, and hired him to perform an independent assessment of the Los Pinos slide and pavement.
Among Ing. Mercurio’s observations, conclusions and recommendations:
- The unsupported pavement is subject to catastrophic failure.
- The rocky material in the hillside is a glassy sand and clay material that rain water can essentially reduce to mud.
- There is high risk of hillside failure, resulting in loss of access to more than 100 homes, including Horizon, La Cima III and Terrazas Del Mar.
- There is high risk of damage to adjacent buildings.
- Without preventative intervention, further failure of the hillside (and the road) is imminent, though it’s hard to predict exactly when.
- Ing. Mercurio recommends prohibiting vehicles driving (or parking) over the undermined pavement; immediate closure of Los Pinos to trucks and other heavy vehicles; and reducing traffic to a single lane near the undermined pavement.
- He further recommends the construction of a large reinforced concrete retention wall to prevent further erosion and to stabilize the street.
An English language version of Ing. Mercurio’s report is included below, and we’ll be posting his report in its original Spanish on the ANA website.
ANA is forwarding Ing. Mercurio’s report to Mayor Davalos, with copies to Obras Publicas, Proteccion Civil, Planning and Transito. We will be following up with them and urgently requesting that the recommended actions be taken immediately. We’ll further update you when we have more news.
REPORT BY CIVIL ENGINEER ANTONIO MERCURIO
The undersigned Specialist Engineer in Structural Calculation, Antonio Mercurio, born in Naples (Italy) on May 29, 1968, as owner of COSTRUCCIONES MERCURIO, has carried out projects in Puerto Vallarta and Guadalajara with a 25 year experience, and who, together with Engineer Egidio Mercurio, on behalf of the Association of Neighbors of Colonia Amapas AC carried out a review and diagnosis of the land located in Paseo de Los Verdes Pinos, next to condominium Los Pinos, in relation to a landslide, of which the following observations are made:
Regarding our visit to the site in the middle of June 2017, and observing an unstable condition of the underlying front of the sidewalk, with partial slip off the shoulder of the street, we observed a section of the street referred to as Los Pinos without support approximately 5 meters by 3meters, the result of an erosion in the supporting hillside.
This condition, which continues to be generated progressively due to the adjacent properties of the street, the constant passage of heavy vehicles and the total absence of functional containment and the lack of a rain gutter, has caused visible damage and failure on the slope.
The rocky material existing in the hillside, which is exposed and identified as glassy sand and clay, when in contact with rainfall is transformed into mud, which has as characteristics clay earth, glassy with total absence of rocks.
These conditions have created a situation of high risk of structural failure of the street, and possible damage in the adjacent residential buildings.
The road in the current state with the lack of support due to the marked defect in the hillside, can collapse, this being possibly catastrophic, by the weight and the vibration resulting from vehicular traffic, in addition to other factors like rain that accelerate the process of sliding of earth.
Without preventive action, the collapse of the slope is imminent. However, it cannot be determined precisely when that collapse could occur, considering that there are other factors that affect the possible damage such as an earthquake, a storm or even a vein of groundwater.
A COLLAPSE, AMONG OTHER THINGS, COULD OCCUR
High risk for the building adjacent to the affected area, in which its structural support can be compromised, in addition to the existence of pools in the area, damage can trigger hundreds of liters of water, on the ground and affected, causing major damage.
– High risk of losing the only vehicular access route, unique access to more than 100 houses and condominiums among which we can mention Horizon, La Cima III and Terrazas del Mar, to name a few.
– The safety coefficients are very low, and stability depends on existing vegetation, which is not strong, due to the absence of big trees, allowing movement of the surface of the slope;
– In case of a seismic movement, the safety coefficients would be reduced even more.
Reasons why consolidation operations are suggested:
– Immediately prohibiting vehicular traffic on the affected (undermined) area. Creating a single line of traffic on that segment of the road.
– Prohibiting the passage of heavy vehicles on the street, including all trucks, especially restricting the passage of more than 3 tons.
-Construction of a retaining wall with reinforced concrete to prevent future erosion, and provide stability and support for the slope that is at risk. Reinforced concrete wall of approx. 40 cm of 60 meters of length with pilasters of maximum height of 12 meters with footings of 2×2. The wall would surround the lot, and from wall to wall are connected through load, all filled and compacted with bench ground. All the size of the reinforcements and the dimensions of the pilasters and walls would be determined with precision after having performed a study of mechanics of soil and resulting structural calculations.
– In my experience, other retention structures such as terraced stone, or stone wall, do not provide the necessary lateral support in this situation, so are not recommended in this case.
– In the case of street collapse caused by slipping of the material in the hillside, the cost of repair and intervention is estimated to be 3 to 4 times greater than the cost of the recommended works for supporting the street and containing the slide, in addition to the great inconvenience of the impossibility of access to the homes served by this street.
URGENT AND IMMEDIATE WORKS.
– STUDY OF SOIL MECHANICS
– STRUCTURAL CALCULATIONS
– Execution of the work in reinforced concrete, as a preventive as explained, allowing access to homes served by road.